3521 lines
125 KiB
Text
3521 lines
125 KiB
Text
How fio works
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-------------
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The first step in getting fio to simulate a desired I/O workload, is writing a
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job file describing that specific setup. A job file may contain any number of
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threads and/or files -- the typical contents of the job file is a *global*
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section defining shared parameters, and one or more job sections describing the
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jobs involved. When run, fio parses this file and sets everything up as
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described. If we break down a job from top to bottom, it contains the following
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basic parameters:
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`I/O type`_
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Defines the I/O pattern issued to the file(s). We may only be reading
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sequentially from this file(s), or we may be writing randomly. Or even
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mixing reads and writes, sequentially or randomly.
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Should we be doing buffered I/O, or direct/raw I/O?
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`Block size`_
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In how large chunks are we issuing I/O? This may be a single value,
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or it may describe a range of block sizes.
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`I/O size`_
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How much data are we going to be reading/writing.
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`I/O engine`_
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How do we issue I/O? We could be memory mapping the file, we could be
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using regular read/write, we could be using splice, async I/O, or even
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SG (SCSI generic sg).
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`I/O depth`_
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If the I/O engine is async, how large a queuing depth do we want to
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maintain?
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`Target file/device`_
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How many files are we spreading the workload over.
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`Threads, processes and job synchronization`_
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How many threads or processes should we spread this workload over.
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The above are the basic parameters defined for a workload, in addition there's a
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multitude of parameters that modify other aspects of how this job behaves.
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Command line options
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--------------------
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.. option:: --debug=type
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Enable verbose tracing of various fio actions. May be ``all`` for all types
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or individual types separated by a comma (e.g. ``--debug=file,mem`` will
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enable file and memory debugging). Currently, additional logging is
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available for:
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*process*
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Dump info related to processes.
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*file*
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Dump info related to file actions.
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*io*
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Dump info related to I/O queuing.
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*mem*
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Dump info related to memory allocations.
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*blktrace*
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Dump info related to blktrace setup.
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*verify*
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Dump info related to I/O verification.
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*all*
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Enable all debug options.
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*random*
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Dump info related to random offset generation.
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*parse*
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Dump info related to option matching and parsing.
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*diskutil*
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Dump info related to disk utilization updates.
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*job:x*
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Dump info only related to job number x.
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*mutex*
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Dump info only related to mutex up/down ops.
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*profile*
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Dump info related to profile extensions.
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*time*
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Dump info related to internal time keeping.
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*net*
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Dump info related to networking connections.
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*rate*
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Dump info related to I/O rate switching.
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*compress*
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Dump info related to log compress/decompress.
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*?* or *help*
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Show available debug options.
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.. option:: --parse-only
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Parse options only, don\'t start any I/O.
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.. option:: --output=filename
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Write output to file `filename`.
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.. option:: --bandwidth-log
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Generate aggregate bandwidth logs.
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.. option:: --minimal
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Print statistics in a terse, semicolon-delimited format.
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.. option:: --append-terse
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Print statistics in selected mode AND terse, semicolon-delimited format.
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**deprecated**, use :option:`--output-format` instead to select multiple
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formats.
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.. option:: --output-format=type
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Set the reporting format to `normal`, `terse`, `json`, or `json+`. Multiple
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formats can be selected, separate by a comma. `terse` is a CSV based
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format. `json+` is like `json`, except it adds a full dump of the latency
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buckets.
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.. option:: --terse-version=type
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Set terse version output format (default 3, or 2 or 4).
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.. option:: --version
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Print version info and exit.
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.. option:: --help
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Print this page.
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.. option:: --cpuclock-test
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Perform test and validation of internal CPU clock.
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.. option:: --crctest=test
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Test the speed of the builtin checksumming functions. If no argument is
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given, all of them are tested. Or a comma separated list can be passed, in
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which case the given ones are tested.
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.. option:: --cmdhelp=command
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Print help information for `command`. May be ``all`` for all commands.
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.. option:: --enghelp=[ioengine[,command]]
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List all commands defined by :option:`ioengine`, or print help for `command`
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defined by :option:`ioengine`. If no :option:`ioengine` is given, list all
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available ioengines.
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.. option:: --showcmd=jobfile
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Turn a job file into command line options.
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.. option:: --readonly
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Turn on safety read-only checks, preventing writes. The ``--readonly``
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option is an extra safety guard to prevent users from accidentally starting
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a write workload when that is not desired. Fio will only write if
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`rw=write/randwrite/rw/randrw` is given. This extra safety net can be used
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as an extra precaution as ``--readonly`` will also enable a write check in
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the I/O engine core to prevent writes due to unknown user space bug(s).
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.. option:: --eta=when
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When real-time ETA estimate should be printed. May be `always`, `never` or
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`auto`.
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.. option:: --eta-newline=time
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Force a new line for every `time` period passed.
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.. option:: --status-interval=time
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Force full status dump every `time` period passed.
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.. option:: --section=name
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Only run specified section in job file. Multiple sections can be specified.
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The ``--section`` option allows one to combine related jobs into one file.
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E.g. one job file could define light, moderate, and heavy sections. Tell
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fio to run only the "heavy" section by giving ``--section=heavy``
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command line option. One can also specify the "write" operations in one
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section and "verify" operation in another section. The ``--section`` option
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only applies to job sections. The reserved *global* section is always
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parsed and used.
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.. option:: --alloc-size=kb
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Set the internal smalloc pool to this size in kb (def 1024). The
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``--alloc-size`` switch allows one to use a larger pool size for smalloc.
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If running large jobs with randommap enabled, fio can run out of memory.
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Smalloc is an internal allocator for shared structures from a fixed size
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memory pool. The pool size defaults to 16M and can grow to 8 pools.
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NOTE: While running :file:`.fio_smalloc.*` backing store files are visible
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in :file:`/tmp`.
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.. option:: --warnings-fatal
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All fio parser warnings are fatal, causing fio to exit with an
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error.
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.. option:: --max-jobs=nr
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Maximum number of threads/processes to support.
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.. option:: --server=args
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Start a backend server, with `args` specifying what to listen to.
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See `Client/Server`_ section.
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.. option:: --daemonize=pidfile
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Background a fio server, writing the pid to the given `pidfile` file.
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.. option:: --client=hostname
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Instead of running the jobs locally, send and run them on the given host or
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set of hosts. See `Client/Server`_ section.
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.. option:: --remote-config=file
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Tell fio server to load this local file.
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.. option:: --idle-prof=option
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Report cpu idleness on a system or percpu basis
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``--idle-prof=system,percpu`` or
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run unit work calibration only ``--idle-prof=calibrate``.
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.. option:: --inflate-log=log
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Inflate and output compressed log.
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.. option:: --trigger-file=file
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Execute trigger cmd when file exists.
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.. option:: --trigger-timeout=t
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Execute trigger at this time.
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.. option:: --trigger=cmd
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Set this command as local trigger.
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.. option:: --trigger-remote=cmd
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Set this command as remote trigger.
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.. option:: --aux-path=path
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Use this path for fio state generated files.
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Any parameters following the options will be assumed to be job files, unless
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they match a job file parameter. Multiple job files can be listed and each job
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file will be regarded as a separate group. Fio will :option:`stonewall`
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execution between each group.
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Job file format
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---------------
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As previously described, fio accepts one or more job files describing what it is
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supposed to do. The job file format is the classic ini file, where the names
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enclosed in [] brackets define the job name. You are free to use any ASCII name
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you want, except *global* which has special meaning. Following the job name is
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a sequence of zero or more parameters, one per line, that define the behavior of
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the job. If the first character in a line is a ';' or a '#', the entire line is
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discarded as a comment.
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A *global* section sets defaults for the jobs described in that file. A job may
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override a *global* section parameter, and a job file may even have several
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*global* sections if so desired. A job is only affected by a *global* section
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residing above it.
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The :option:`--cmdhelp` option also lists all options. If used with an `option`
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argument, :option:`--cmdhelp` will detail the given `option`.
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See the `examples/` directory for inspiration on how to write job files. Note
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the copyright and license requirements currently apply to `examples/` files.
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So let's look at a really simple job file that defines two processes, each
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randomly reading from a 128MiB file:
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.. code-block:: ini
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; -- start job file --
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[global]
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rw=randread
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size=128m
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[job1]
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[job2]
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; -- end job file --
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As you can see, the job file sections themselves are empty as all the described
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parameters are shared. As no :option:`filename` option is given, fio makes up a
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`filename` for each of the jobs as it sees fit. On the command line, this job
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would look as follows::
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$ fio --name=global --rw=randread --size=128m --name=job1 --name=job2
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Let's look at an example that has a number of processes writing randomly to
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files:
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.. code-block:: ini
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; -- start job file --
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[random-writers]
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ioengine=libaio
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iodepth=4
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rw=randwrite
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bs=32k
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direct=0
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size=64m
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numjobs=4
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; -- end job file --
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Here we have no *global* section, as we only have one job defined anyway. We
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want to use async I/O here, with a depth of 4 for each file. We also increased
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the buffer size used to 32KiB and define numjobs to 4 to fork 4 identical
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jobs. The result is 4 processes each randomly writing to their own 64MiB
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file. Instead of using the above job file, you could have given the parameters
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on the command line. For this case, you would specify::
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$ fio --name=random-writers --ioengine=libaio --iodepth=4 --rw=randwrite --bs=32k --direct=0 --size=64m --numjobs=4
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When fio is utilized as a basis of any reasonably large test suite, it might be
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desirable to share a set of standardized settings across multiple job files.
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Instead of copy/pasting such settings, any section may pull in an external
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:file:`filename.fio` file with *include filename* directive, as in the following
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example::
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; -- start job file including.fio --
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[global]
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filename=/tmp/test
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filesize=1m
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include glob-include.fio
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[test]
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rw=randread
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bs=4k
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time_based=1
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runtime=10
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include test-include.fio
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; -- end job file including.fio --
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.. code-block:: ini
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; -- start job file glob-include.fio --
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thread=1
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group_reporting=1
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; -- end job file glob-include.fio --
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.. code-block:: ini
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; -- start job file test-include.fio --
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ioengine=libaio
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iodepth=4
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; -- end job file test-include.fio --
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Settings pulled into a section apply to that section only (except *global*
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section). Include directives may be nested in that any included file may contain
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further include directive(s). Include files may not contain [] sections.
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Environment variables
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~~~~~~~~~~~~~~~~~~~~~
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Fio also supports environment variable expansion in job files. Any sub-string of
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the form ``${VARNAME}`` as part of an option value (in other words, on the right
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of the '='), will be expanded to the value of the environment variable called
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`VARNAME`. If no such environment variable is defined, or `VARNAME` is the
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empty string, the empty string will be substituted.
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As an example, let's look at a sample fio invocation and job file::
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$ SIZE=64m NUMJOBS=4 fio jobfile.fio
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.. code-block:: ini
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; -- start job file --
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[random-writers]
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rw=randwrite
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size=${SIZE}
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numjobs=${NUMJOBS}
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; -- end job file --
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This will expand to the following equivalent job file at runtime:
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.. code-block:: ini
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; -- start job file --
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[random-writers]
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rw=randwrite
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size=64m
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numjobs=4
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; -- end job file --
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Fio ships with a few example job files, you can also look there for inspiration.
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Reserved keywords
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~~~~~~~~~~~~~~~~~
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Additionally, fio has a set of reserved keywords that will be replaced
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internally with the appropriate value. Those keywords are:
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**$pagesize**
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The architecture page size of the running system.
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**$mb_memory**
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Megabytes of total memory in the system.
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**$ncpus**
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Number of online available CPUs.
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These can be used on the command line or in the job file, and will be
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automatically substituted with the current system values when the job is
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run. Simple math is also supported on these keywords, so you can perform actions
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like::
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size=8*$mb_memory
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and get that properly expanded to 8 times the size of memory in the machine.
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Job file parameters
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-------------------
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This section describes in details each parameter associated with a job. Some
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parameters take an option of a given type, such as an integer or a
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string. Anywhere a numeric value is required, an arithmetic expression may be
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used, provided it is surrounded by parentheses. Supported operators are:
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- addition (+)
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- subtraction (-)
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- multiplication (*)
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- division (/)
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- modulus (%)
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- exponentiation (^)
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For time values in expressions, units are microseconds by default. This is
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different than for time values not in expressions (not enclosed in
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parentheses). The following types are used:
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Parameter types
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~~~~~~~~~~~~~~~
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**str**
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String. This is a sequence of alpha characters.
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**time**
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Integer with possible time suffix. In seconds unless otherwise
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specified, use e.g. 10m for 10 minutes. Accepts s/m/h for seconds, minutes,
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and hours, and accepts 'ms' (or 'msec') for milliseconds, and 'us' (or
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'usec') for microseconds.
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.. _int:
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**int**
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Integer. A whole number value, which may contain an integer prefix
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and an integer suffix:
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[*integer prefix*] **number** [*integer suffix*]
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The optional *integer prefix* specifies the number's base. The default
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is decimal. *0x* specifies hexadecimal.
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The optional *integer suffix* specifies the number's units, and includes an
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optional unit prefix and an optional unit. For quantities of data, the
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default unit is bytes. For quantities of time, the default unit is seconds.
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With :option:`kb_base` =1000, fio follows international standards for unit
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prefixes. To specify power-of-10 decimal values defined in the
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International System of Units (SI):
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* *Ki* -- means kilo (K) or 1000
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* *Mi* -- means mega (M) or 1000**2
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* *Gi* -- means giga (G) or 1000**3
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* *Ti* -- means tera (T) or 1000**4
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* *Pi* -- means peta (P) or 1000**5
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To specify power-of-2 binary values defined in IEC 80000-13:
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* *k* -- means kibi (Ki) or 1024
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* *M* -- means mebi (Mi) or 1024**2
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* *G* -- means gibi (Gi) or 1024**3
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* *T* -- means tebi (Ti) or 1024**4
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* *P* -- means pebi (Pi) or 1024**5
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With :option:`kb_base` =1024 (the default), the unit prefixes are opposite
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from those specified in the SI and IEC 80000-13 standards to provide
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compatibility with old scripts. For example, 4k means 4096.
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For quantities of data, an optional unit of 'B' may be included
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(e.g., 'kB' is the same as 'k').
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The *integer suffix* is not case sensitive (e.g., m/mi mean mebi/mega,
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not milli). 'b' and 'B' both mean byte, not bit.
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Examples with :option:`kb_base` =1000:
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* *4 KiB*: 4096, 4096b, 4096B, 4ki, 4kib, 4kiB, 4Ki, 4KiB
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* *1 MiB*: 1048576, 1mi, 1024ki
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* *1 MB*: 1000000, 1m, 1000k
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* *1 TiB*: 1099511627776, 1ti, 1024gi, 1048576mi
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* *1 TB*: 1000000000, 1t, 1000m, 1000000k
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Examples with :option:`kb_base` =1024 (default):
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* *4 KiB*: 4096, 4096b, 4096B, 4k, 4kb, 4kB, 4K, 4KB
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* *1 MiB*: 1048576, 1m, 1024k
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* *1 MB*: 1000000, 1mi, 1000ki
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* *1 TiB*: 1099511627776, 1t, 1024g, 1048576m
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* *1 TB*: 1000000000, 1ti, 1000mi, 1000000ki
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To specify times (units are not case sensitive):
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* *D* -- means days
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* *H* -- means hours
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* *M* -- mean minutes
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* *s* -- or sec means seconds (default)
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* *ms* -- or *msec* means milliseconds
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* *us* -- or *usec* means microseconds
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If the option accepts an upper and lower range, use a colon ':' or
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minus '-' to separate such values. See :ref:`irange <irange>`.
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If the lower value specified happens to be larger than the upper value,
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two values are swapped.
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.. _bool:
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**bool**
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Boolean. Usually parsed as an integer, however only defined for
|
|
true and false (1 and 0).
|
|
|
|
.. _irange:
|
|
|
|
**irange**
|
|
Integer range with suffix. Allows value range to be given, such as
|
|
1024-4096. A colon may also be used as the separator, e.g. 1k:4k. If the
|
|
option allows two sets of ranges, they can be specified with a ',' or '/'
|
|
delimiter: 1k-4k/8k-32k. Also see :ref:`int <int>`.
|
|
|
|
**float_list**
|
|
A list of floating point numbers, separated by a ':' character.
|
|
|
|
|
|
Units
|
|
~~~~~
|
|
|
|
.. option:: kb_base=int
|
|
|
|
Select the interpretation of unit prefixes in input parameters.
|
|
|
|
**1000**
|
|
Inputs comply with IEC 80000-13 and the International
|
|
System of Units (SI). Use:
|
|
|
|
- power-of-2 values with IEC prefixes (e.g., KiB)
|
|
- power-of-10 values with SI prefixes (e.g., kB)
|
|
|
|
**1024**
|
|
Compatibility mode (default). To avoid breaking old scripts:
|
|
|
|
- power-of-2 values with SI prefixes
|
|
- power-of-10 values with IEC prefixes
|
|
|
|
See :option:`bs` for more details on input parameters.
|
|
|
|
Outputs always use correct prefixes. Most outputs include both
|
|
side-by-side, like::
|
|
|
|
bw=2383.3kB/s (2327.4KiB/s)
|
|
|
|
If only one value is reported, then kb_base selects the one to use:
|
|
|
|
**1000** -- SI prefixes
|
|
|
|
**1024** -- IEC prefixes
|
|
|
|
.. option:: unit_base=int
|
|
|
|
Base unit for reporting. Allowed values are:
|
|
|
|
**0**
|
|
Use auto-detection (default).
|
|
**8**
|
|
Byte based.
|
|
**1**
|
|
Bit based.
|
|
|
|
|
|
With the above in mind, here follows the complete list of fio job parameters.
|
|
|
|
|
|
Job description
|
|
~~~~~~~~~~~~~~~
|
|
|
|
.. option:: name=str
|
|
|
|
ASCII name of the job. This may be used to override the name printed by fio
|
|
for this job. Otherwise the job name is used. On the command line this
|
|
parameter has the special purpose of also signaling the start of a new job.
|
|
|
|
.. option:: description=str
|
|
|
|
Text description of the job. Doesn't do anything except dump this text
|
|
description when this job is run. It's not parsed.
|
|
|
|
.. option:: loops=int
|
|
|
|
Run the specified number of iterations of this job. Used to repeat the same
|
|
workload a given number of times. Defaults to 1.
|
|
|
|
.. option:: numjobs=int
|
|
|
|
Create the specified number of clones of this job. Each clone of job
|
|
is spawned as an independent thread or process. May be used to setup a
|
|
larger number of threads/processes doing the same thing. Each thread is
|
|
reported separately; to see statistics for all clones as a whole, use
|
|
:option:`group_reporting` in conjunction with :option:`new_group`.
|
|
See :option:`--max-jobs`.
|
|
|
|
|
|
Time related parameters
|
|
~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
.. option:: runtime=time
|
|
|
|
Tell fio to terminate processing after the specified period of time. It
|
|
can be quite hard to determine for how long a specified job will run, so
|
|
this parameter is handy to cap the total runtime to a given time. When
|
|
the unit is omitted, the value is given in seconds.
|
|
|
|
.. option:: time_based
|
|
|
|
If set, fio will run for the duration of the :option:`runtime` specified
|
|
even if the file(s) are completely read or written. It will simply loop over
|
|
the same workload as many times as the :option:`runtime` allows.
|
|
|
|
.. option:: startdelay=irange(time)
|
|
|
|
Delay start of job for the specified number of seconds. Supports all time
|
|
suffixes to allow specification of hours, minutes, seconds and milliseconds
|
|
-- seconds are the default if a unit is omitted. Can be given as a range
|
|
which causes each thread to choose randomly out of the range.
|
|
|
|
.. option:: ramp_time=time
|
|
|
|
If set, fio will run the specified workload for this amount of time before
|
|
logging any performance numbers. Useful for letting performance settle
|
|
before logging results, thus minimizing the runtime required for stable
|
|
results. Note that the ``ramp_time`` is considered lead in time for a job,
|
|
thus it will increase the total runtime if a special timeout or
|
|
:option:`runtime` is specified. When the unit is omitted, the value is
|
|
given in seconds.
|
|
|
|
.. option:: clocksource=str
|
|
|
|
Use the given clocksource as the base of timing. The supported options are:
|
|
|
|
**gettimeofday**
|
|
:manpage:`gettimeofday(2)`
|
|
|
|
**clock_gettime**
|
|
:manpage:`clock_gettime(2)`
|
|
|
|
**cpu**
|
|
Internal CPU clock source
|
|
|
|
cpu is the preferred clocksource if it is reliable, as it is very fast (and
|
|
fio is heavy on time calls). Fio will automatically use this clocksource if
|
|
it's supported and considered reliable on the system it is running on,
|
|
unless another clocksource is specifically set. For x86/x86-64 CPUs, this
|
|
means supporting TSC Invariant.
|
|
|
|
.. option:: gtod_reduce=bool
|
|
|
|
Enable all of the :manpage:`gettimeofday(2)` reducing options
|
|
(:option:`disable_clat`, :option:`disable_slat`, :option:`disable_bw_measurement`) plus
|
|
reduce precision of the timeout somewhat to really shrink the
|
|
:manpage:`gettimeofday(2)` call count. With this option enabled, we only do
|
|
about 0.4% of the :manpage:`gettimeofday(2)` calls we would have done if all
|
|
time keeping was enabled.
|
|
|
|
.. option:: gtod_cpu=int
|
|
|
|
Sometimes it's cheaper to dedicate a single thread of execution to just
|
|
getting the current time. Fio (and databases, for instance) are very
|
|
intensive on :manpage:`gettimeofday(2)` calls. With this option, you can set
|
|
one CPU aside for doing nothing but logging current time to a shared memory
|
|
location. Then the other threads/processes that run I/O workloads need only
|
|
copy that segment, instead of entering the kernel with a
|
|
:manpage:`gettimeofday(2)` call. The CPU set aside for doing these time
|
|
calls will be excluded from other uses. Fio will manually clear it from the
|
|
CPU mask of other jobs.
|
|
|
|
|
|
Target file/device
|
|
~~~~~~~~~~~~~~~~~~
|
|
|
|
.. option:: directory=str
|
|
|
|
Prefix filenames with this directory. Used to place files in a different
|
|
location than :file:`./`. You can specify a number of directories by
|
|
separating the names with a ':' character. These directories will be
|
|
assigned equally distributed to job clones creates with :option:`numjobs` as
|
|
long as they are using generated filenames. If specific `filename(s)` are
|
|
set fio will use the first listed directory, and thereby matching the
|
|
`filename` semantic which generates a file each clone if not specified, but
|
|
let all clones use the same if set.
|
|
|
|
See the :option:`filename` option for escaping certain characters.
|
|
|
|
.. option:: filename=str
|
|
|
|
Fio normally makes up a `filename` based on the job name, thread number, and
|
|
file number. If you want to share files between threads in a job or several
|
|
jobs with fixed file paths, specify a `filename` for each of them to override
|
|
the default. If the ioengine is file based, you can specify a number of files
|
|
by separating the names with a ':' colon. So if you wanted a job to open
|
|
:file:`/dev/sda` and :file:`/dev/sdb` as the two working files, you would use
|
|
``filename=/dev/sda:/dev/sdb``. This also means that whenever this option is
|
|
specified, :option:`nrfiles` is ignored. The size of regular files specified
|
|
by this option will be :option:`size` divided by number of files unless
|
|
explicit size is specified by :option:`filesize`.
|
|
|
|
On Windows, disk devices are accessed as :file:`\\\\.\\PhysicalDrive0` for
|
|
the first device, :file:`\\\\.\\PhysicalDrive1` for the second etc.
|
|
Note: Windows and FreeBSD prevent write access to areas
|
|
of the disk containing in-use data (e.g. filesystems). If the wanted
|
|
`filename` does need to include a colon, then escape that with a ``\``
|
|
character. For instance, if the `filename` is :file:`/dev/dsk/foo@3,0:c`,
|
|
then you would use ``filename="/dev/dsk/foo@3,0\:c"``. The
|
|
:file:`-` is a reserved name, meaning stdin or stdout. Which of the two
|
|
depends on the read/write direction set.
|
|
|
|
.. option:: filename_format=str
|
|
|
|
If sharing multiple files between jobs, it is usually necessary to have fio
|
|
generate the exact names that you want. By default, fio will name a file
|
|
based on the default file format specification of
|
|
:file:`jobname.jobnumber.filenumber`. With this option, that can be
|
|
customized. Fio will recognize and replace the following keywords in this
|
|
string:
|
|
|
|
**$jobname**
|
|
The name of the worker thread or process.
|
|
**$jobnum**
|
|
The incremental number of the worker thread or process.
|
|
**$filenum**
|
|
The incremental number of the file for that worker thread or
|
|
process.
|
|
|
|
To have dependent jobs share a set of files, this option can be set to have
|
|
fio generate filenames that are shared between the two. For instance, if
|
|
:file:`testfiles.$filenum` is specified, file number 4 for any job will be
|
|
named :file:`testfiles.4`. The default of :file:`$jobname.$jobnum.$filenum`
|
|
will be used if no other format specifier is given.
|
|
|
|
.. option:: unique_filename=bool
|
|
|
|
To avoid collisions between networked clients, fio defaults to prefixing any
|
|
generated filenames (with a directory specified) with the source of the
|
|
client connecting. To disable this behavior, set this option to 0.
|
|
|
|
.. option:: opendir=str
|
|
|
|
Recursively open any files below directory `str`.
|
|
|
|
.. option:: lockfile=str
|
|
|
|
Fio defaults to not locking any files before it does I/O to them. If a file
|
|
or file descriptor is shared, fio can serialize I/O to that file to make the
|
|
end result consistent. This is usual for emulating real workloads that share
|
|
files. The lock modes are:
|
|
|
|
**none**
|
|
No locking. The default.
|
|
**exclusive**
|
|
Only one thread or process may do I/O at a time, excluding all
|
|
others.
|
|
**readwrite**
|
|
Read-write locking on the file. Many readers may
|
|
access the file at the same time, but writes get exclusive access.
|
|
|
|
.. option:: nrfiles=int
|
|
|
|
Number of files to use for this job. Defaults to 1. The size of files
|
|
will be :option:`size` divided by this unless explicit size is specified by
|
|
:option:`filesize`. Files are created for each thread separately, and each
|
|
file will have a file number within its name by default, as explained in
|
|
:option:`filename` section.
|
|
|
|
|
|
.. option:: openfiles=int
|
|
|
|
Number of files to keep open at the same time. Defaults to the same as
|
|
:option:`nrfiles`, can be set smaller to limit the number simultaneous
|
|
opens.
|
|
|
|
.. option:: file_service_type=str
|
|
|
|
Defines how fio decides which file from a job to service next. The following
|
|
types are defined:
|
|
|
|
**random**
|
|
Choose a file at random.
|
|
|
|
**roundrobin**
|
|
Round robin over opened files. This is the default.
|
|
|
|
**sequential**
|
|
Finish one file before moving on to the next. Multiple files can
|
|
still be open depending on 'openfiles'.
|
|
|
|
**zipf**
|
|
Use a *Zipf* distribution to decide what file to access.
|
|
|
|
**pareto**
|
|
Use a *Pareto* distribution to decide what file to access.
|
|
|
|
**gauss**
|
|
Use a *Gaussian* (normal) distribution to decide what file to
|
|
access.
|
|
|
|
For *random*, *roundrobin*, and *sequential*, a postfix can be appended to
|
|
tell fio how many I/Os to issue before switching to a new file. For example,
|
|
specifying ``file_service_type=random:8`` would cause fio to issue
|
|
8 I/Os before selecting a new file at random. For the non-uniform
|
|
distributions, a floating point postfix can be given to influence how the
|
|
distribution is skewed. See :option:`random_distribution` for a description
|
|
of how that would work.
|
|
|
|
.. option:: ioscheduler=str
|
|
|
|
Attempt to switch the device hosting the file to the specified I/O scheduler
|
|
before running.
|
|
|
|
.. option:: create_serialize=bool
|
|
|
|
If true, serialize the file creation for the jobs. This may be handy to
|
|
avoid interleaving of data files, which may greatly depend on the filesystem
|
|
used and even the number of processors in the system.
|
|
|
|
.. option:: create_fsync=bool
|
|
|
|
fsync the data file after creation. This is the default.
|
|
|
|
.. option:: create_on_open=bool
|
|
|
|
Don't pre-setup the files for I/O, just create open() when it's time to do
|
|
I/O to that file.
|
|
|
|
.. option:: create_only=bool
|
|
|
|
If true, fio will only run the setup phase of the job. If files need to be
|
|
laid out or updated on disk, only that will be done. The actual job contents
|
|
are not executed.
|
|
|
|
.. option:: allow_file_create=bool
|
|
|
|
If true, fio is permitted to create files as part of its workload. This is
|
|
the default behavior. If this option is false, then fio will error out if
|
|
the files it needs to use don't already exist. Default: true.
|
|
|
|
.. option:: allow_mounted_write=bool
|
|
|
|
If this isn't set, fio will abort jobs that are destructive (e.g. that write)
|
|
to what appears to be a mounted device or partition. This should help catch
|
|
creating inadvertently destructive tests, not realizing that the test will
|
|
destroy data on the mounted file system. Note that some platforms don't allow
|
|
writing against a mounted device regardless of this option. Default: false.
|
|
|
|
.. option:: pre_read=bool
|
|
|
|
If this is given, files will be pre-read into memory before starting the
|
|
given I/O operation. This will also clear the :option:`invalidate` flag,
|
|
since it is pointless to pre-read and then drop the cache. This will only
|
|
work for I/O engines that are seek-able, since they allow you to read the
|
|
same data multiple times. Thus it will not work on e.g. network or splice I/O.
|
|
|
|
.. option:: unlink=bool
|
|
|
|
Unlink the job files when done. Not the default, as repeated runs of that
|
|
job would then waste time recreating the file set again and again.
|
|
|
|
.. option:: unlink_each_loop=bool
|
|
|
|
Unlink job files after each iteration or loop.
|
|
|
|
.. option:: zonesize=int
|
|
|
|
Divide a file into zones of the specified size. See :option:`zoneskip`.
|
|
|
|
.. option:: zonerange=int
|
|
|
|
Give size of an I/O zone. See :option:`zoneskip`.
|
|
|
|
.. option:: zoneskip=int
|
|
|
|
Skip the specified number of bytes when :option:`zonesize` data has been
|
|
read. The two zone options can be used to only do I/O on zones of a file.
|
|
|
|
|
|
I/O type
|
|
~~~~~~~~
|
|
|
|
.. option:: direct=bool
|
|
|
|
If value is true, use non-buffered I/O. This is usually O_DIRECT. Note that
|
|
ZFS on Solaris doesn't support direct I/O. On Windows the synchronous
|
|
ioengines don't support direct I/O. Default: false.
|
|
|
|
.. option:: atomic=bool
|
|
|
|
If value is true, attempt to use atomic direct I/O. Atomic writes are
|
|
guaranteed to be stable once acknowledged by the operating system. Only
|
|
Linux supports O_ATOMIC right now.
|
|
|
|
.. option:: buffered=bool
|
|
|
|
If value is true, use buffered I/O. This is the opposite of the
|
|
:option:`direct` option. Defaults to true.
|
|
|
|
.. option:: readwrite=str, rw=str
|
|
|
|
Type of I/O pattern. Accepted values are:
|
|
|
|
**read**
|
|
Sequential reads.
|
|
**write**
|
|
Sequential writes.
|
|
**trim**
|
|
Sequential trims (Linux block devices only).
|
|
**randwrite**
|
|
Random writes.
|
|
**randread**
|
|
Random reads.
|
|
**randtrim**
|
|
Random trims (Linux block devices only).
|
|
**rw,readwrite**
|
|
Sequential mixed reads and writes.
|
|
**randrw**
|
|
Random mixed reads and writes.
|
|
**trimwrite**
|
|
Sequential trim+write sequences. Blocks will be trimmed first,
|
|
then the same blocks will be written to.
|
|
|
|
Fio defaults to read if the option is not specified. For the mixed I/O
|
|
types, the default is to split them 50/50. For certain types of I/O the
|
|
result may still be skewed a bit, since the speed may be different. It is
|
|
possible to specify a number of I/O's to do before getting a new offset,
|
|
this is done by appending a ``:<nr>`` to the end of the string given. For a
|
|
random read, it would look like ``rw=randread:8`` for passing in an offset
|
|
modifier with a value of 8. If the suffix is used with a sequential I/O
|
|
pattern, then the value specified will be added to the generated offset for
|
|
each I/O. For instance, using ``rw=write:4k`` will skip 4k for every
|
|
write. It turns sequential I/O into sequential I/O with holes. See the
|
|
:option:`rw_sequencer` option.
|
|
|
|
.. option:: rw_sequencer=str
|
|
|
|
If an offset modifier is given by appending a number to the ``rw=<str>``
|
|
line, then this option controls how that number modifies the I/O offset
|
|
being generated. Accepted values are:
|
|
|
|
**sequential**
|
|
Generate sequential offset.
|
|
**identical**
|
|
Generate the same offset.
|
|
|
|
``sequential`` is only useful for random I/O, where fio would normally
|
|
generate a new random offset for every I/O. If you append e.g. 8 to randread,
|
|
you would get a new random offset for every 8 I/O's. The result would be a
|
|
seek for only every 8 I/O's, instead of for every I/O. Use ``rw=randread:8``
|
|
to specify that. As sequential I/O is already sequential, setting
|
|
``sequential`` for that would not result in any differences. ``identical``
|
|
behaves in a similar fashion, except it sends the same offset 8 number of
|
|
times before generating a new offset.
|
|
|
|
.. option:: unified_rw_reporting=bool
|
|
|
|
Fio normally reports statistics on a per data direction basis, meaning that
|
|
reads, writes, and trims are accounted and reported separately. If this
|
|
option is set fio sums the results and report them as "mixed" instead.
|
|
|
|
.. option:: randrepeat=bool
|
|
|
|
Seed the random number generator used for random I/O patterns in a
|
|
predictable way so the pattern is repeatable across runs. Default: true.
|
|
|
|
.. option:: allrandrepeat=bool
|
|
|
|
Seed all random number generators in a predictable way so results are
|
|
repeatable across runs. Default: false.
|
|
|
|
.. option:: randseed=int
|
|
|
|
Seed the random number generators based on this seed value, to be able to
|
|
control what sequence of output is being generated. If not set, the random
|
|
sequence depends on the :option:`randrepeat` setting.
|
|
|
|
.. option:: fallocate=str
|
|
|
|
Whether pre-allocation is performed when laying down files.
|
|
Accepted values are:
|
|
|
|
**none**
|
|
Do not pre-allocate space.
|
|
|
|
**posix**
|
|
Pre-allocate via :manpage:`posix_fallocate(3)`.
|
|
|
|
**keep**
|
|
Pre-allocate via :manpage:`fallocate(2)` with
|
|
FALLOC_FL_KEEP_SIZE set.
|
|
|
|
**0**
|
|
Backward-compatible alias for **none**.
|
|
|
|
**1**
|
|
Backward-compatible alias for **posix**.
|
|
|
|
May not be available on all supported platforms. **keep** is only available
|
|
on Linux. If using ZFS on Solaris this must be set to **none** because ZFS
|
|
doesn't support it. Default: **posix**.
|
|
|
|
.. option:: fadvise_hint=str
|
|
|
|
Use :manpage:`posix_fadvise(2)` to advise the kernel on what I/O patterns
|
|
are likely to be issued. Accepted values are:
|
|
|
|
**0**
|
|
Backwards-compatible hint for "no hint".
|
|
|
|
**1**
|
|
Backwards compatible hint for "advise with fio workload type". This
|
|
uses **FADV_RANDOM** for a random workload, and **FADV_SEQUENTIAL**
|
|
for a sequential workload.
|
|
|
|
**sequential**
|
|
Advise using **FADV_SEQUENTIAL**.
|
|
|
|
**random**
|
|
Advise using **FADV_RANDOM**.
|
|
|
|
.. option:: fadvise_stream=int
|
|
|
|
Use :manpage:`posix_fadvise(2)` to advise the kernel what stream ID the
|
|
writes issued belong to. Only supported on Linux. Note, this option may
|
|
change going forward.
|
|
|
|
.. option:: offset=int
|
|
|
|
Start I/O at the given offset in the file. The data before the given offset
|
|
will not be touched. This effectively caps the file size at `real_size -
|
|
offset`. Can be combined with :option:`size` to constrain the start and
|
|
end range that I/O will be done within.
|
|
|
|
.. option:: offset_increment=int
|
|
|
|
If this is provided, then the real offset becomes `offset + offset_increment
|
|
* thread_number`, where the thread number is a counter that starts at 0 and
|
|
is incremented for each sub-job (i.e. when :option:`numjobs` option is
|
|
specified). This option is useful if there are several jobs which are
|
|
intended to operate on a file in parallel disjoint segments, with even
|
|
spacing between the starting points.
|
|
|
|
.. option:: number_ios=int
|
|
|
|
Fio will normally perform I/Os until it has exhausted the size of the region
|
|
set by :option:`size`, or if it exhaust the allocated time (or hits an error
|
|
condition). With this setting, the range/size can be set independently of
|
|
the number of I/Os to perform. When fio reaches this number, it will exit
|
|
normally and report status. Note that this does not extend the amount of I/O
|
|
that will be done, it will only stop fio if this condition is met before
|
|
other end-of-job criteria.
|
|
|
|
.. option:: fsync=int
|
|
|
|
If writing to a file, issue a sync of the dirty data for every number of
|
|
blocks given. For example, if you give 32 as a parameter, fio will sync the
|
|
file for every 32 writes issued. If fio is using non-buffered I/O, we may
|
|
not sync the file. The exception is the sg I/O engine, which synchronizes
|
|
the disk cache anyway. Defaults to 0, which means no sync every certain
|
|
number of writes.
|
|
|
|
.. option:: fdatasync=int
|
|
|
|
Like :option:`fsync` but uses :manpage:`fdatasync(2)` to only sync data and
|
|
not metadata blocks. In Windows, FreeBSD, and DragonFlyBSD there is no
|
|
:manpage:`fdatasync(2)`, this falls back to using :manpage:`fsync(2)`.
|
|
Defaults to 0, which means no sync data every certain number of writes.
|
|
|
|
.. option:: write_barrier=int
|
|
|
|
Make every `N-th` write a barrier write.
|
|
|
|
.. option:: sync_file_range=str:val
|
|
|
|
Use :manpage:`sync_file_range(2)` for every `val` number of write
|
|
operations. Fio will track range of writes that have happened since the last
|
|
:manpage:`sync_file_range(2)` call. `str` can currently be one or more of:
|
|
|
|
**wait_before**
|
|
SYNC_FILE_RANGE_WAIT_BEFORE
|
|
**write**
|
|
SYNC_FILE_RANGE_WRITE
|
|
**wait_after**
|
|
SYNC_FILE_RANGE_WAIT_AFTER
|
|
|
|
So if you do ``sync_file_range=wait_before,write:8``, fio would use
|
|
``SYNC_FILE_RANGE_WAIT_BEFORE | SYNC_FILE_RANGE_WRITE`` for every 8
|
|
writes. Also see the :manpage:`sync_file_range(2)` man page. This option is
|
|
Linux specific.
|
|
|
|
.. option:: overwrite=bool
|
|
|
|
If true, writes to a file will always overwrite existing data. If the file
|
|
doesn't already exist, it will be created before the write phase begins. If
|
|
the file exists and is large enough for the specified write phase, nothing
|
|
will be done.
|
|
|
|
.. option:: end_fsync=bool
|
|
|
|
If true, fsync file contents when a write stage has completed.
|
|
|
|
.. option:: fsync_on_close=bool
|
|
|
|
If true, fio will :manpage:`fsync(2)` a dirty file on close. This differs
|
|
from end_fsync in that it will happen on every file close, not just at the
|
|
end of the job.
|
|
|
|
.. option:: rwmixread=int
|
|
|
|
Percentage of a mixed workload that should be reads. Default: 50.
|
|
|
|
.. option:: rwmixwrite=int
|
|
|
|
Percentage of a mixed workload that should be writes. If both
|
|
:option:`rwmixread` and :option:`rwmixwrite` is given and the values do not
|
|
add up to 100%, the latter of the two will be used to override the
|
|
first. This may interfere with a given rate setting, if fio is asked to
|
|
limit reads or writes to a certain rate. If that is the case, then the
|
|
distribution may be skewed. Default: 50.
|
|
|
|
.. option:: random_distribution=str:float[,str:float][,str:float]
|
|
|
|
By default, fio will use a completely uniform random distribution when asked
|
|
to perform random I/O. Sometimes it is useful to skew the distribution in
|
|
specific ways, ensuring that some parts of the data is more hot than others.
|
|
fio includes the following distribution models:
|
|
|
|
**random**
|
|
Uniform random distribution
|
|
|
|
**zipf**
|
|
Zipf distribution
|
|
|
|
**pareto**
|
|
Pareto distribution
|
|
|
|
**gauss**
|
|
Normal (Gaussian) distribution
|
|
|
|
**zoned**
|
|
Zoned random distribution
|
|
|
|
When using a **zipf** or **pareto** distribution, an input value is also
|
|
needed to define the access pattern. For **zipf**, this is the `zipf
|
|
theta`. For **pareto**, it's the `Pareto power`. Fio includes a test
|
|
program, :command:`genzipf`, that can be used visualize what the given input
|
|
values will yield in terms of hit rates. If you wanted to use **zipf** with
|
|
a `theta` of 1.2, you would use ``random_distribution=zipf:1.2`` as the
|
|
option. If a non-uniform model is used, fio will disable use of the random
|
|
map. For the **gauss** distribution, a normal deviation is supplied as a
|
|
value between 0 and 100.
|
|
|
|
For a **zoned** distribution, fio supports specifying percentages of I/O
|
|
access that should fall within what range of the file or device. For
|
|
example, given a criteria of:
|
|
|
|
* 60% of accesses should be to the first 10%
|
|
* 30% of accesses should be to the next 20%
|
|
* 8% of accesses should be to to the next 30%
|
|
* 2% of accesses should be to the next 40%
|
|
|
|
we can define that through zoning of the random accesses. For the above
|
|
example, the user would do::
|
|
|
|
random_distribution=zoned:60/10:30/20:8/30:2/40
|
|
|
|
similarly to how :option:`bssplit` works for setting ranges and percentages
|
|
of block sizes. Like :option:`bssplit`, it's possible to specify separate
|
|
zones for reads, writes, and trims. If just one set is given, it'll apply to
|
|
all of them.
|
|
|
|
.. option:: percentage_random=int[,int][,int]
|
|
|
|
For a random workload, set how big a percentage should be random. This
|
|
defaults to 100%, in which case the workload is fully random. It can be set
|
|
from anywhere from 0 to 100. Setting it to 0 would make the workload fully
|
|
sequential. Any setting in between will result in a random mix of sequential
|
|
and random I/O, at the given percentages. Comma-separated values may be
|
|
specified for reads, writes, and trims as described in :option:`blocksize`.
|
|
|
|
.. option:: norandommap
|
|
|
|
Normally fio will cover every block of the file when doing random I/O. If
|
|
this option is given, fio will just get a new random offset without looking
|
|
at past I/O history. This means that some blocks may not be read or written,
|
|
and that some blocks may be read/written more than once. If this option is
|
|
used with :option:`verify` and multiple blocksizes (via :option:`bsrange`),
|
|
only intact blocks are verified, i.e., partially-overwritten blocks are
|
|
ignored.
|
|
|
|
.. option:: softrandommap=bool
|
|
|
|
See :option:`norandommap`. If fio runs with the random block map enabled and
|
|
it fails to allocate the map, if this option is set it will continue without
|
|
a random block map. As coverage will not be as complete as with random maps,
|
|
this option is disabled by default.
|
|
|
|
.. option:: random_generator=str
|
|
|
|
Fio supports the following engines for generating
|
|
I/O offsets for random I/O:
|
|
|
|
**tausworthe**
|
|
Strong 2^88 cycle random number generator
|
|
**lfsr**
|
|
Linear feedback shift register generator
|
|
**tausworthe64**
|
|
Strong 64-bit 2^258 cycle random number generator
|
|
|
|
**tausworthe** is a strong random number generator, but it requires tracking
|
|
on the side if we want to ensure that blocks are only read or written
|
|
once. **LFSR** guarantees that we never generate the same offset twice, and
|
|
it's also less computationally expensive. It's not a true random generator,
|
|
however, though for I/O purposes it's typically good enough. **LFSR** only
|
|
works with single block sizes, not with workloads that use multiple block
|
|
sizes. If used with such a workload, fio may read or write some blocks
|
|
multiple times. The default value is **tausworthe**, unless the required
|
|
space exceeds 2^32 blocks. If it does, then **tausworthe64** is
|
|
selected automatically.
|
|
|
|
|
|
Block size
|
|
~~~~~~~~~~
|
|
|
|
.. option:: blocksize=int[,int][,int], bs=int[,int][,int]
|
|
|
|
The block size in bytes used for I/O units. Default: 4096. A single value
|
|
applies to reads, writes, and trims. Comma-separated values may be
|
|
specified for reads, writes, and trims. A value not terminated in a comma
|
|
applies to subsequent types.
|
|
|
|
Examples:
|
|
|
|
**bs=256k**
|
|
means 256k for reads, writes and trims.
|
|
|
|
**bs=8k,32k**
|
|
means 8k for reads, 32k for writes and trims.
|
|
|
|
**bs=8k,32k,**
|
|
means 8k for reads, 32k for writes, and default for trims.
|
|
|
|
**bs=,8k**
|
|
means default for reads, 8k for writes and trims.
|
|
|
|
**bs=,8k,**
|
|
means default for reads, 8k for writes, and default for writes.
|
|
|
|
.. option:: blocksize_range=irange[,irange][,irange], bsrange=irange[,irange][,irange]
|
|
|
|
A range of block sizes in bytes for I/O units. The issued I/O unit will
|
|
always be a multiple of the minimum size, unless
|
|
:option:`blocksize_unaligned` is set.
|
|
|
|
Comma-separated ranges may be specified for reads, writes, and trims as
|
|
described in :option:`blocksize`.
|
|
|
|
Example: ``bsrange=1k-4k,2k-8k``.
|
|
|
|
.. option:: bssplit=str[,str][,str]
|
|
|
|
Sometimes you want even finer grained control of the block sizes issued, not
|
|
just an even split between them. This option allows you to weight various
|
|
block sizes, so that you are able to define a specific amount of block sizes
|
|
issued. The format for this option is::
|
|
|
|
bssplit=blocksize/percentage:blocksize/percentage
|
|
|
|
for as many block sizes as needed. So if you want to define a workload that
|
|
has 50% 64k blocks, 10% 4k blocks, and 40% 32k blocks, you would write::
|
|
|
|
bssplit=4k/10:64k/50:32k/40
|
|
|
|
Ordering does not matter. If the percentage is left blank, fio will fill in
|
|
the remaining values evenly. So a bssplit option like this one::
|
|
|
|
bssplit=4k/50:1k/:32k/
|
|
|
|
would have 50% 4k ios, and 25% 1k and 32k ios. The percentages always add up
|
|
to 100, if bssplit is given a range that adds up to more, it will error out.
|
|
|
|
Comma-separated values may be specified for reads, writes, and trims as
|
|
described in :option:`blocksize`.
|
|
|
|
If you want a workload that has 50% 2k reads and 50% 4k reads, while having
|
|
90% 4k writes and 10% 8k writes, you would specify::
|
|
|
|
bssplit=2k/50:4k/50,4k/90,8k/10
|
|
|
|
.. option:: blocksize_unaligned, bs_unaligned
|
|
|
|
If set, fio will issue I/O units with any size within
|
|
:option:`blocksize_range`, not just multiples of the minimum size. This
|
|
typically won't work with direct I/O, as that normally requires sector
|
|
alignment.
|
|
|
|
.. option:: bs_is_seq_rand
|
|
|
|
If this option is set, fio will use the normal read,write blocksize settings
|
|
as sequential,random blocksize settings instead. Any random read or write
|
|
will use the WRITE blocksize settings, and any sequential read or write will
|
|
use the READ blocksize settings.
|
|
|
|
.. option:: blockalign=int[,int][,int], ba=int[,int][,int]
|
|
|
|
Boundary to which fio will align random I/O units. Default:
|
|
:option:`blocksize`. Minimum alignment is typically 512b for using direct
|
|
I/O, though it usually depends on the hardware block size. This option is
|
|
mutually exclusive with using a random map for files, so it will turn off
|
|
that option. Comma-separated values may be specified for reads, writes, and
|
|
trims as described in :option:`blocksize`.
|
|
|
|
|
|
Buffers and memory
|
|
~~~~~~~~~~~~~~~~~~
|
|
|
|
.. option:: zero_buffers
|
|
|
|
Initialize buffers with all zeros. Default: fill buffers with random data.
|
|
|
|
.. option:: refill_buffers
|
|
|
|
If this option is given, fio will refill the I/O buffers on every
|
|
submit. The default is to only fill it at init time and reuse that
|
|
data. Only makes sense if zero_buffers isn't specified, naturally. If data
|
|
verification is enabled, `refill_buffers` is also automatically enabled.
|
|
|
|
.. option:: scramble_buffers=bool
|
|
|
|
If :option:`refill_buffers` is too costly and the target is using data
|
|
deduplication, then setting this option will slightly modify the I/O buffer
|
|
contents to defeat normal de-dupe attempts. This is not enough to defeat
|
|
more clever block compression attempts, but it will stop naive dedupe of
|
|
blocks. Default: true.
|
|
|
|
.. option:: buffer_compress_percentage=int
|
|
|
|
If this is set, then fio will attempt to provide I/O buffer content (on
|
|
WRITEs) that compress to the specified level. Fio does this by providing a
|
|
mix of random data and a fixed pattern. The fixed pattern is either zeroes,
|
|
or the pattern specified by :option:`buffer_pattern`. If the pattern option
|
|
is used, it might skew the compression ratio slightly. Note that this is per
|
|
block size unit, for file/disk wide compression level that matches this
|
|
setting, you'll also want to set :option:`refill_buffers`.
|
|
|
|
.. option:: buffer_compress_chunk=int
|
|
|
|
See :option:`buffer_compress_percentage`. This setting allows fio to manage
|
|
how big the ranges of random data and zeroed data is. Without this set, fio
|
|
will provide :option:`buffer_compress_percentage` of blocksize random data,
|
|
followed by the remaining zeroed. With this set to some chunk size smaller
|
|
than the block size, fio can alternate random and zeroed data throughout the
|
|
I/O buffer.
|
|
|
|
.. option:: buffer_pattern=str
|
|
|
|
If set, fio will fill the I/O buffers with this pattern. If not set, the
|
|
contents of I/O buffers is defined by the other options related to buffer
|
|
contents. The setting can be any pattern of bytes, and can be prefixed with
|
|
0x for hex values. It may also be a string, where the string must then be
|
|
wrapped with ``""``, e.g.::
|
|
|
|
buffer_pattern="abcd"
|
|
|
|
or::
|
|
|
|
buffer_pattern=-12
|
|
|
|
or::
|
|
|
|
buffer_pattern=0xdeadface
|
|
|
|
Also you can combine everything together in any order::
|
|
|
|
buffer_pattern=0xdeadface"abcd"-12
|
|
|
|
.. option:: dedupe_percentage=int
|
|
|
|
If set, fio will generate this percentage of identical buffers when
|
|
writing. These buffers will be naturally dedupable. The contents of the
|
|
buffers depend on what other buffer compression settings have been set. It's
|
|
possible to have the individual buffers either fully compressible, or not at
|
|
all. This option only controls the distribution of unique buffers.
|
|
|
|
.. option:: invalidate=bool
|
|
|
|
Invalidate the buffer/page cache parts for this file prior to starting
|
|
I/O if the platform and file type support it. Defaults to true.
|
|
This will be ignored if :option:`pre_read` is also specified for the
|
|
same job.
|
|
|
|
.. option:: sync=bool
|
|
|
|
Use synchronous I/O for buffered writes. For the majority of I/O engines,
|
|
this means using O_SYNC. Default: false.
|
|
|
|
.. option:: iomem=str, mem=str
|
|
|
|
Fio can use various types of memory as the I/O unit buffer. The allowed
|
|
values are:
|
|
|
|
**malloc**
|
|
Use memory from :manpage:`malloc(3)` as the buffers. Default memory
|
|
type.
|
|
|
|
**shm**
|
|
Use shared memory as the buffers. Allocated through
|
|
:manpage:`shmget(2)`.
|
|
|
|
**shmhuge**
|
|
Same as shm, but use huge pages as backing.
|
|
|
|
**mmap**
|
|
Use mmap to allocate buffers. May either be anonymous memory, or can
|
|
be file backed if a filename is given after the option. The format
|
|
is `mem=mmap:/path/to/file`.
|
|
|
|
**mmaphuge**
|
|
Use a memory mapped huge file as the buffer backing. Append filename
|
|
after mmaphuge, ala `mem=mmaphuge:/hugetlbfs/file`.
|
|
|
|
**mmapshared**
|
|
Same as mmap, but use a MMAP_SHARED mapping.
|
|
|
|
**cudamalloc**
|
|
Use GPU memory as the buffers for GPUDirect RDMA benchmark.
|
|
|
|
The area allocated is a function of the maximum allowed bs size for the job,
|
|
multiplied by the I/O depth given. Note that for **shmhuge** and
|
|
**mmaphuge** to work, the system must have free huge pages allocated. This
|
|
can normally be checked and set by reading/writing
|
|
:file:`/proc/sys/vm/nr_hugepages` on a Linux system. Fio assumes a huge page
|
|
is 4MiB in size. So to calculate the number of huge pages you need for a
|
|
given job file, add up the I/O depth of all jobs (normally one unless
|
|
:option:`iodepth` is used) and multiply by the maximum bs set. Then divide
|
|
that number by the huge page size. You can see the size of the huge pages in
|
|
:file:`/proc/meminfo`. If no huge pages are allocated by having a non-zero
|
|
number in `nr_hugepages`, using **mmaphuge** or **shmhuge** will fail. Also
|
|
see :option:`hugepage-size`.
|
|
|
|
**mmaphuge** also needs to have hugetlbfs mounted and the file location
|
|
should point there. So if it's mounted in :file:`/huge`, you would use
|
|
`mem=mmaphuge:/huge/somefile`.
|
|
|
|
.. option:: iomem_align=int
|
|
|
|
This indicates the memory alignment of the I/O memory buffers. Note that
|
|
the given alignment is applied to the first I/O unit buffer, if using
|
|
:option:`iodepth` the alignment of the following buffers are given by the
|
|
:option:`bs` used. In other words, if using a :option:`bs` that is a
|
|
multiple of the page sized in the system, all buffers will be aligned to
|
|
this value. If using a :option:`bs` that is not page aligned, the alignment
|
|
of subsequent I/O memory buffers is the sum of the :option:`iomem_align` and
|
|
:option:`bs` used.
|
|
|
|
.. option:: hugepage-size=int
|
|
|
|
Defines the size of a huge page. Must at least be equal to the system
|
|
setting, see :file:`/proc/meminfo`. Defaults to 4MiB. Should probably
|
|
always be a multiple of megabytes, so using ``hugepage-size=Xm`` is the
|
|
preferred way to set this to avoid setting a non-pow-2 bad value.
|
|
|
|
.. option:: lockmem=int
|
|
|
|
Pin the specified amount of memory with :manpage:`mlock(2)`. Can be used to
|
|
simulate a smaller amount of memory. The amount specified is per worker.
|
|
|
|
|
|
I/O size
|
|
~~~~~~~~
|
|
|
|
.. option:: size=int
|
|
|
|
The total size of file I/O for each thread of this job. Fio will run until
|
|
this many bytes has been transferred, unless runtime is limited by other options
|
|
(such as :option:`runtime`, for instance, or increased/decreased by :option:`io_size`).
|
|
Fio will divide this size between the available files determined by options
|
|
such as :option:`nrfiles`, :option:`filename`, unless :option:`filesize` is
|
|
specified by the job. If the result of division happens to be 0, the size is
|
|
set to the physical size of the given files or devices if they exist.
|
|
If this option is not specified, fio will use the full size of the given
|
|
files or devices. If the files do not exist, size must be given. It is also
|
|
possible to give size as a percentage between 1 and 100. If ``size=20%`` is
|
|
given, fio will use 20% of the full size of the given files or devices.
|
|
Can be combined with :option:`offset` to constrain the start and end range
|
|
that I/O will be done within.
|
|
|
|
.. option:: io_size=int, io_limit=int
|
|
|
|
Normally fio operates within the region set by :option:`size`, which means
|
|
that the :option:`size` option sets both the region and size of I/O to be
|
|
performed. Sometimes that is not what you want. With this option, it is
|
|
possible to define just the amount of I/O that fio should do. For instance,
|
|
if :option:`size` is set to 20GiB and :option:`io_size` is set to 5GiB, fio
|
|
will perform I/O within the first 20GiB but exit when 5GiB have been
|
|
done. The opposite is also possible -- if :option:`size` is set to 20GiB,
|
|
and :option:`io_size` is set to 40GiB, then fio will do 40GiB of I/O within
|
|
the 0..20GiB region.
|
|
|
|
.. option:: filesize=int
|
|
|
|
Individual file sizes. May be a range, in which case fio will select sizes
|
|
for files at random within the given range and limited to :option:`size` in
|
|
total (if that is given). If not given, each created file is the same size.
|
|
This option overrides :option:`size` in terms of file size, which means
|
|
this value is used as a fixed size or possible range of each file.
|
|
|
|
.. option:: file_append=bool
|
|
|
|
Perform I/O after the end of the file. Normally fio will operate within the
|
|
size of a file. If this option is set, then fio will append to the file
|
|
instead. This has identical behavior to setting :option:`offset` to the size
|
|
of a file. This option is ignored on non-regular files.
|
|
|
|
.. option:: fill_device=bool, fill_fs=bool
|
|
|
|
Sets size to something really large and waits for ENOSPC (no space left on
|
|
device) as the terminating condition. Only makes sense with sequential
|
|
write. For a read workload, the mount point will be filled first then I/O
|
|
started on the result. This option doesn't make sense if operating on a raw
|
|
device node, since the size of that is already known by the file system.
|
|
Additionally, writing beyond end-of-device will not return ENOSPC there.
|
|
|
|
|
|
I/O engine
|
|
~~~~~~~~~~
|
|
|
|
.. option:: ioengine=str
|
|
|
|
Defines how the job issues I/O to the file. The following types are defined:
|
|
|
|
**sync**
|
|
Basic :manpage:`read(2)` or :manpage:`write(2)`
|
|
I/O. :manpage:`lseek(2)` is used to position the I/O location.
|
|
See :option:`fsync` and :option:`fdatasync` for syncing write I/Os.
|
|
|
|
**psync**
|
|
Basic :manpage:`pread(2)` or :manpage:`pwrite(2)` I/O. Default on
|
|
all supported operating systems except for Windows.
|
|
|
|
**vsync**
|
|
Basic :manpage:`readv(2)` or :manpage:`writev(2)` I/O. Will emulate
|
|
queuing by coalescing adjacent I/Os into a single submission.
|
|
|
|
**pvsync**
|
|
Basic :manpage:`preadv(2)` or :manpage:`pwritev(2)` I/O.
|
|
|
|
**pvsync2**
|
|
Basic :manpage:`preadv2(2)` or :manpage:`pwritev2(2)` I/O.
|
|
|
|
**libaio**
|
|
Linux native asynchronous I/O. Note that Linux may only support
|
|
queued behaviour with non-buffered I/O (set ``direct=1`` or
|
|
``buffered=0``).
|
|
This engine defines engine specific options.
|
|
|
|
**posixaio**
|
|
POSIX asynchronous I/O using :manpage:`aio_read(3)` and
|
|
:manpage:`aio_write(3)`.
|
|
|
|
**solarisaio**
|
|
Solaris native asynchronous I/O.
|
|
|
|
**windowsaio**
|
|
Windows native asynchronous I/O. Default on Windows.
|
|
|
|
**mmap**
|
|
File is memory mapped with :manpage:`mmap(2)` and data copied
|
|
to/from using :manpage:`memcpy(3)`.
|
|
|
|
**splice**
|
|
:manpage:`splice(2)` is used to transfer the data and
|
|
:manpage:`vmsplice(2)` to transfer data from user space to the
|
|
kernel.
|
|
|
|
**sg**
|
|
SCSI generic sg v3 I/O. May either be synchronous using the SG_IO
|
|
ioctl, or if the target is an sg character device we use
|
|
:manpage:`read(2)` and :manpage:`write(2)` for asynchronous
|
|
I/O. Requires filename option to specify either block or character
|
|
devices.
|
|
|
|
**null**
|
|
Doesn't transfer any data, just pretends to. This is mainly used to
|
|
exercise fio itself and for debugging/testing purposes.
|
|
|
|
**net**
|
|
Transfer over the network to given ``host:port``. Depending on the
|
|
:option:`protocol` used, the :option:`hostname`, :option:`port`,
|
|
:option:`listen` and :option:`filename` options are used to specify
|
|
what sort of connection to make, while the :option:`protocol` option
|
|
determines which protocol will be used. This engine defines engine
|
|
specific options.
|
|
|
|
**netsplice**
|
|
Like **net**, but uses :manpage:`splice(2)` and
|
|
:manpage:`vmsplice(2)` to map data and send/receive.
|
|
This engine defines engine specific options.
|
|
|
|
**cpuio**
|
|
Doesn't transfer any data, but burns CPU cycles according to the
|
|
:option:`cpuload` and :option:`cpuchunks` options. Setting
|
|
:option:`cpuload` =85 will cause that job to do nothing but burn 85%
|
|
of the CPU. In case of SMP machines, use :option:`numjobs`
|
|
=<no_of_cpu> to get desired CPU usage, as the cpuload only loads a
|
|
single CPU at the desired rate. A job never finishes unless there is
|
|
at least one non-cpuio job.
|
|
|
|
**guasi**
|
|
The GUASI I/O engine is the Generic Userspace Asyncronous Syscall
|
|
Interface approach to async I/O. See
|
|
|
|
http://www.xmailserver.org/guasi-lib.html
|
|
|
|
for more info on GUASI.
|
|
|
|
**rdma**
|
|
The RDMA I/O engine supports both RDMA memory semantics
|
|
(RDMA_WRITE/RDMA_READ) and channel semantics (Send/Recv) for the
|
|
InfiniBand, RoCE and iWARP protocols.
|
|
|
|
**falloc**
|
|
I/O engine that does regular fallocate to simulate data transfer as
|
|
fio ioengine.
|
|
|
|
DDIR_READ
|
|
does fallocate(,mode = FALLOC_FL_KEEP_SIZE,).
|
|
|
|
DDIR_WRITE
|
|
does fallocate(,mode = 0).
|
|
|
|
DDIR_TRIM
|
|
does fallocate(,mode = FALLOC_FL_KEEP_SIZE|FALLOC_FL_PUNCH_HOLE).
|
|
|
|
**ftruncate**
|
|
I/O engine that sends :manpage:`ftruncate(2)` operations in response
|
|
to write (DDIR_WRITE) events. Each ftruncate issued sets the file's
|
|
size to the current block offset. Block size is ignored.
|
|
|
|
**e4defrag**
|
|
I/O engine that does regular EXT4_IOC_MOVE_EXT ioctls to simulate
|
|
defragment activity in request to DDIR_WRITE event.
|
|
|
|
**rbd**
|
|
I/O engine supporting direct access to Ceph Rados Block Devices
|
|
(RBD) via librbd without the need to use the kernel rbd driver. This
|
|
ioengine defines engine specific options.
|
|
|
|
**gfapi**
|
|
Using Glusterfs libgfapi sync interface to direct access to
|
|
Glusterfs volumes without having to go through FUSE. This ioengine
|
|
defines engine specific options.
|
|
|
|
**gfapi_async**
|
|
Using Glusterfs libgfapi async interface to direct access to
|
|
Glusterfs volumes without having to go through FUSE. This ioengine
|
|
defines engine specific options.
|
|
|
|
**libhdfs**
|
|
Read and write through Hadoop (HDFS). The :file:`filename` option
|
|
is used to specify host,port of the hdfs name-node to connect. This
|
|
engine interprets offsets a little differently. In HDFS, files once
|
|
created cannot be modified. So random writes are not possible. To
|
|
imitate this, libhdfs engine expects bunch of small files to be
|
|
created over HDFS, and engine will randomly pick a file out of those
|
|
files based on the offset generated by fio backend. (see the example
|
|
job file to create such files, use ``rw=write`` option). Please
|
|
note, you might want to set necessary environment variables to work
|
|
with hdfs/libhdfs properly. Each job uses its own connection to
|
|
HDFS.
|
|
|
|
**mtd**
|
|
Read, write and erase an MTD character device (e.g.,
|
|
:file:`/dev/mtd0`). Discards are treated as erases. Depending on the
|
|
underlying device type, the I/O may have to go in a certain pattern,
|
|
e.g., on NAND, writing sequentially to erase blocks and discarding
|
|
before overwriting. The writetrim mode works well for this
|
|
constraint.
|
|
|
|
**pmemblk**
|
|
Read and write using filesystem DAX to a file on a filesystem
|
|
mounted with DAX on a persistent memory device through the NVML
|
|
libpmemblk library.
|
|
|
|
**dev-dax**
|
|
Read and write using device DAX to a persistent memory device (e.g.,
|
|
/dev/dax0.0) through the NVML libpmem library.
|
|
|
|
**external**
|
|
Prefix to specify loading an external I/O engine object file. Append
|
|
the engine filename, e.g. ``ioengine=external:/tmp/foo.o`` to load
|
|
ioengine :file:`foo.o` in :file:`/tmp`.
|
|
|
|
|
|
I/O engine specific parameters
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
In addition, there are some parameters which are only valid when a specific
|
|
ioengine is in use. These are used identically to normal parameters, with the
|
|
caveat that when used on the command line, they must come after the
|
|
:option:`ioengine` that defines them is selected.
|
|
|
|
.. option:: userspace_reap : [libaio]
|
|
|
|
Normally, with the libaio engine in use, fio will use the
|
|
:manpage:`io_getevents(2)` system call to reap newly returned events. With
|
|
this flag turned on, the AIO ring will be read directly from user-space to
|
|
reap events. The reaping mode is only enabled when polling for a minimum of
|
|
0 events (e.g. when :option:`iodepth_batch_complete` `=0`).
|
|
|
|
.. option:: hipri : [pvsync2]
|
|
|
|
Set RWF_HIPRI on I/O, indicating to the kernel that it's of higher priority
|
|
than normal.
|
|
|
|
.. option:: cpuload=int : [cpuio]
|
|
|
|
Attempt to use the specified percentage of CPU cycles. This is a mandatory
|
|
option when using cpuio I/O engine.
|
|
|
|
.. option:: cpuchunks=int : [cpuio]
|
|
|
|
Split the load into cycles of the given time. In microseconds.
|
|
|
|
.. option:: exit_on_io_done=bool : [cpuio]
|
|
|
|
Detect when I/O threads are done, then exit.
|
|
|
|
.. option:: hostname=str : [netsplice] [net]
|
|
|
|
The host name or IP address to use for TCP or UDP based I/O. If the job is
|
|
a TCP listener or UDP reader, the host name is not used and must be omitted
|
|
unless it is a valid UDP multicast address.
|
|
|
|
.. option:: namenode=str : [libhdfs]
|
|
|
|
The host name or IP address of a HDFS cluster namenode to contact.
|
|
|
|
.. option:: port=int
|
|
|
|
[netsplice], [net]
|
|
|
|
The TCP or UDP port to bind to or connect to. If this is used with
|
|
:option:`numjobs` to spawn multiple instances of the same job type, then
|
|
this will be the starting port number since fio will use a range of
|
|
ports.
|
|
|
|
[libhdfs]
|
|
|
|
the listening port of the HFDS cluster namenode.
|
|
|
|
.. option:: interface=str : [netsplice] [net]
|
|
|
|
The IP address of the network interface used to send or receive UDP
|
|
multicast.
|
|
|
|
.. option:: ttl=int : [netsplice] [net]
|
|
|
|
Time-to-live value for outgoing UDP multicast packets. Default: 1.
|
|
|
|
.. option:: nodelay=bool : [netsplice] [net]
|
|
|
|
Set TCP_NODELAY on TCP connections.
|
|
|
|
.. option:: protocol=str : [netsplice] [net]
|
|
|
|
.. option:: proto=str : [netsplice] [net]
|
|
|
|
The network protocol to use. Accepted values are:
|
|
|
|
**tcp**
|
|
Transmission control protocol.
|
|
**tcpv6**
|
|
Transmission control protocol V6.
|
|
**udp**
|
|
User datagram protocol.
|
|
**udpv6**
|
|
User datagram protocol V6.
|
|
**unix**
|
|
UNIX domain socket.
|
|
|
|
When the protocol is TCP or UDP, the port must also be given, as well as the
|
|
hostname if the job is a TCP listener or UDP reader. For unix sockets, the
|
|
normal filename option should be used and the port is invalid.
|
|
|
|
.. option:: listen : [net]
|
|
|
|
For TCP network connections, tell fio to listen for incoming connections
|
|
rather than initiating an outgoing connection. The :option:`hostname` must
|
|
be omitted if this option is used.
|
|
|
|
.. option:: pingpong : [net]
|
|
|
|
Normally a network writer will just continue writing data, and a network
|
|
reader will just consume packages. If ``pingpong=1`` is set, a writer will
|
|
send its normal payload to the reader, then wait for the reader to send the
|
|
same payload back. This allows fio to measure network latencies. The
|
|
submission and completion latencies then measure local time spent sending or
|
|
receiving, and the completion latency measures how long it took for the
|
|
other end to receive and send back. For UDP multicast traffic
|
|
``pingpong=1`` should only be set for a single reader when multiple readers
|
|
are listening to the same address.
|
|
|
|
.. option:: window_size : [net]
|
|
|
|
Set the desired socket buffer size for the connection.
|
|
|
|
.. option:: mss : [net]
|
|
|
|
Set the TCP maximum segment size (TCP_MAXSEG).
|
|
|
|
.. option:: donorname=str : [e4defrag]
|
|
|
|
File will be used as a block donor(swap extents between files).
|
|
|
|
.. option:: inplace=int : [e4defrag]
|
|
|
|
Configure donor file blocks allocation strategy:
|
|
|
|
**0**
|
|
Default. Preallocate donor's file on init.
|
|
**1**
|
|
Allocate space immediately inside defragment event, and free right
|
|
after event.
|
|
|
|
.. option:: clustername=str : [rbd]
|
|
|
|
Specifies the name of the Ceph cluster.
|
|
|
|
.. option:: rbdname=str : [rbd]
|
|
|
|
Specifies the name of the RBD.
|
|
|
|
.. option:: pool=str : [rbd]
|
|
|
|
Specifies the name of the Ceph pool containing RBD.
|
|
|
|
.. option:: clientname=str : [rbd]
|
|
|
|
Specifies the username (without the 'client.' prefix) used to access the
|
|
Ceph cluster. If the *clustername* is specified, the *clientname* shall be
|
|
the full *type.id* string. If no type. prefix is given, fio will add
|
|
'client.' by default.
|
|
|
|
.. option:: skip_bad=bool : [mtd]
|
|
|
|
Skip operations against known bad blocks.
|
|
|
|
.. option:: hdfsdirectory : [libhdfs]
|
|
|
|
libhdfs will create chunk in this HDFS directory.
|
|
|
|
.. option:: chunk_size : [libhdfs]
|
|
|
|
the size of the chunk to use for each file.
|
|
|
|
|
|
I/O depth
|
|
~~~~~~~~~
|
|
|
|
.. option:: iodepth=int
|
|
|
|
Number of I/O units to keep in flight against the file. Note that
|
|
increasing *iodepth* beyond 1 will not affect synchronous ioengines (except
|
|
for small degrees when :option:`verify_async` is in use). Even async
|
|
engines may impose OS restrictions causing the desired depth not to be
|
|
achieved. This may happen on Linux when using libaio and not setting
|
|
:option:`direct` =1, since buffered I/O is not async on that OS. Keep an
|
|
eye on the I/O depth distribution in the fio output to verify that the
|
|
achieved depth is as expected. Default: 1.
|
|
|
|
.. option:: iodepth_batch_submit=int, iodepth_batch=int
|
|
|
|
This defines how many pieces of I/O to submit at once. It defaults to 1
|
|
which means that we submit each I/O as soon as it is available, but can be
|
|
raised to submit bigger batches of I/O at the time. If it is set to 0 the
|
|
:option:`iodepth` value will be used.
|
|
|
|
.. option:: iodepth_batch_complete_min=int, iodepth_batch_complete=int
|
|
|
|
This defines how many pieces of I/O to retrieve at once. It defaults to 1
|
|
which means that we'll ask for a minimum of 1 I/O in the retrieval process
|
|
from the kernel. The I/O retrieval will go on until we hit the limit set by
|
|
:option:`iodepth_low`. If this variable is set to 0, then fio will always
|
|
check for completed events before queuing more I/O. This helps reduce I/O
|
|
latency, at the cost of more retrieval system calls.
|
|
|
|
.. option:: iodepth_batch_complete_max=int
|
|
|
|
This defines maximum pieces of I/O to retrieve at once. This variable should
|
|
be used along with :option:`iodepth_batch_complete_min` =int variable,
|
|
specifying the range of min and max amount of I/O which should be
|
|
retrieved. By default it is equal to :option:`iodepth_batch_complete_min`
|
|
value.
|
|
|
|
Example #1::
|
|
|
|
iodepth_batch_complete_min=1
|
|
iodepth_batch_complete_max=<iodepth>
|
|
|
|
which means that we will retrieve at least 1 I/O and up to the whole
|
|
submitted queue depth. If none of I/O has been completed yet, we will wait.
|
|
|
|
Example #2::
|
|
|
|
iodepth_batch_complete_min=0
|
|
iodepth_batch_complete_max=<iodepth>
|
|
|
|
which means that we can retrieve up to the whole submitted queue depth, but
|
|
if none of I/O has been completed yet, we will NOT wait and immediately exit
|
|
the system call. In this example we simply do polling.
|
|
|
|
.. option:: iodepth_low=int
|
|
|
|
The low water mark indicating when to start filling the queue
|
|
again. Defaults to the same as :option:`iodepth`, meaning that fio will
|
|
attempt to keep the queue full at all times. If :option:`iodepth` is set to
|
|
e.g. 16 and *iodepth_low* is set to 4, then after fio has filled the queue of
|
|
16 requests, it will let the depth drain down to 4 before starting to fill
|
|
it again.
|
|
|
|
.. option:: io_submit_mode=str
|
|
|
|
This option controls how fio submits the I/O to the I/O engine. The default
|
|
is `inline`, which means that the fio job threads submit and reap I/O
|
|
directly. If set to `offload`, the job threads will offload I/O submission
|
|
to a dedicated pool of I/O threads. This requires some coordination and thus
|
|
has a bit of extra overhead, especially for lower queue depth I/O where it
|
|
can increase latencies. The benefit is that fio can manage submission rates
|
|
independently of the device completion rates. This avoids skewed latency
|
|
reporting if I/O gets back up on the device side (the coordinated omission
|
|
problem).
|
|
|
|
|
|
I/O rate
|
|
~~~~~~~~
|
|
|
|
.. option:: thinktime=time
|
|
|
|
Stall the job for the specified period of time after an I/O has completed before issuing the
|
|
next. May be used to simulate processing being done by an application.
|
|
When the unit is omitted, the value is given in microseconds. See
|
|
:option:`thinktime_blocks` and :option:`thinktime_spin`.
|
|
|
|
.. option:: thinktime_spin=time
|
|
|
|
Only valid if :option:`thinktime` is set - pretend to spend CPU time doing
|
|
something with the data received, before falling back to sleeping for the
|
|
rest of the period specified by :option:`thinktime`. When the unit is
|
|
omitted, the value is given in microseconds.
|
|
|
|
.. option:: thinktime_blocks=int
|
|
|
|
Only valid if :option:`thinktime` is set - control how many blocks to issue,
|
|
before waiting `thinktime` usecs. If not set, defaults to 1 which will make
|
|
fio wait `thinktime` usecs after every block. This effectively makes any
|
|
queue depth setting redundant, since no more than 1 I/O will be queued
|
|
before we have to complete it and do our thinktime. In other words, this
|
|
setting effectively caps the queue depth if the latter is larger.
|
|
|
|
.. option:: rate=int[,int][,int]
|
|
|
|
Cap the bandwidth used by this job. The number is in bytes/sec, the normal
|
|
suffix rules apply. Comma-separated values may be specified for reads,
|
|
writes, and trims as described in :option:`blocksize`.
|
|
|
|
.. option:: rate_min=int[,int][,int]
|
|
|
|
Tell fio to do whatever it can to maintain at least this bandwidth. Failing
|
|
to meet this requirement will cause the job to exit. Comma-separated values
|
|
may be specified for reads, writes, and trims as described in
|
|
:option:`blocksize`.
|
|
|
|
.. option:: rate_iops=int[,int][,int]
|
|
|
|
Cap the bandwidth to this number of IOPS. Basically the same as
|
|
:option:`rate`, just specified independently of bandwidth. If the job is
|
|
given a block size range instead of a fixed value, the smallest block size
|
|
is used as the metric. Comma-separated values may be specified for reads,
|
|
writes, and trims as described in :option:`blocksize`.
|
|
|
|
.. option:: rate_iops_min=int[,int][,int]
|
|
|
|
If fio doesn't meet this rate of I/O, it will cause the job to exit.
|
|
Comma-separated values may be specified for reads, writes, and trims as
|
|
described in :option:`blocksize`.
|
|
|
|
.. option:: rate_process=str
|
|
|
|
This option controls how fio manages rated I/O submissions. The default is
|
|
`linear`, which submits I/O in a linear fashion with fixed delays between
|
|
I/Os that gets adjusted based on I/O completion rates. If this is set to
|
|
`poisson`, fio will submit I/O based on a more real world random request
|
|
flow, known as the Poisson process
|
|
(https://en.wikipedia.org/wiki/Poisson_point_process). The lambda will be
|
|
10^6 / IOPS for the given workload.
|
|
|
|
|
|
I/O latency
|
|
~~~~~~~~~~~
|
|
|
|
.. option:: latency_target=time
|
|
|
|
If set, fio will attempt to find the max performance point that the given
|
|
workload will run at while maintaining a latency below this target. When
|
|
the unit is omitted, the value is given in microseconds. See
|
|
:option:`latency_window` and :option:`latency_percentile`.
|
|
|
|
.. option:: latency_window=time
|
|
|
|
Used with :option:`latency_target` to specify the sample window that the job
|
|
is run at varying queue depths to test the performance. When the unit is
|
|
omitted, the value is given in microseconds.
|
|
|
|
.. option:: latency_percentile=float
|
|
|
|
The percentage of I/Os that must fall within the criteria specified by
|
|
:option:`latency_target` and :option:`latency_window`. If not set, this
|
|
defaults to 100.0, meaning that all I/Os must be equal or below to the value
|
|
set by :option:`latency_target`.
|
|
|
|
.. option:: max_latency=time
|
|
|
|
If set, fio will exit the job with an ETIMEDOUT error if it exceeds this
|
|
maximum latency. When the unit is omitted, the value is given in
|
|
microseconds.
|
|
|
|
.. option:: rate_cycle=int
|
|
|
|
Average bandwidth for :option:`rate` and :option:`rate_min` over this number
|
|
of milliseconds.
|
|
|
|
|
|
I/O replay
|
|
~~~~~~~~~~
|
|
|
|
.. option:: write_iolog=str
|
|
|
|
Write the issued I/O patterns to the specified file. See
|
|
:option:`read_iolog`. Specify a separate file for each job, otherwise the
|
|
iologs will be interspersed and the file may be corrupt.
|
|
|
|
.. option:: read_iolog=str
|
|
|
|
Open an iolog with the specified file name and replay the I/O patterns it
|
|
contains. This can be used to store a workload and replay it sometime
|
|
later. The iolog given may also be a blktrace binary file, which allows fio
|
|
to replay a workload captured by :command:`blktrace`. See
|
|
:manpage:`blktrace(8)` for how to capture such logging data. For blktrace
|
|
replay, the file needs to be turned into a blkparse binary data file first
|
|
(``blkparse <device> -o /dev/null -d file_for_fio.bin``).
|
|
|
|
.. option:: replay_no_stall=int
|
|
|
|
When replaying I/O with :option:`read_iolog` the default behavior is to
|
|
attempt to respect the time stamps within the log and replay them with the
|
|
appropriate delay between IOPS. By setting this variable fio will not
|
|
respect the timestamps and attempt to replay them as fast as possible while
|
|
still respecting ordering. The result is the same I/O pattern to a given
|
|
device, but different timings.
|
|
|
|
.. option:: replay_redirect=str
|
|
|
|
While replaying I/O patterns using :option:`read_iolog` the default behavior
|
|
is to replay the IOPS onto the major/minor device that each IOP was recorded
|
|
from. This is sometimes undesirable because on a different machine those
|
|
major/minor numbers can map to a different device. Changing hardware on the
|
|
same system can also result in a different major/minor mapping.
|
|
``replay_redirect`` causes all IOPS to be replayed onto the single specified
|
|
device regardless of the device it was recorded
|
|
from. i.e. :option:`replay_redirect` = :file:`/dev/sdc` would cause all I/O
|
|
in the blktrace or iolog to be replayed onto :file:`/dev/sdc`. This means
|
|
multiple devices will be replayed onto a single device, if the trace
|
|
contains multiple devices. If you want multiple devices to be replayed
|
|
concurrently to multiple redirected devices you must blkparse your trace
|
|
into separate traces and replay them with independent fio invocations.
|
|
Unfortunately this also breaks the strict time ordering between multiple
|
|
device accesses.
|
|
|
|
.. option:: replay_align=int
|
|
|
|
Force alignment of I/O offsets and lengths in a trace to this power of 2
|
|
value.
|
|
|
|
.. option:: replay_scale=int
|
|
|
|
Scale sector offsets down by this factor when replaying traces.
|
|
|
|
|
|
Threads, processes and job synchronization
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
.. option:: thread
|
|
|
|
Fio defaults to forking jobs, however if this option is given, fio will use
|
|
POSIX Threads function :manpage:`pthread_create(3)` to create threads instead
|
|
of forking processes.
|
|
|
|
.. option:: wait_for=str
|
|
|
|
Specifies the name of the already defined job to wait for. Single waitee
|
|
name only may be specified. If set, the job won't be started until all
|
|
workers of the waitee job are done.
|
|
|
|
``wait_for`` operates on the job name basis, so there are a few
|
|
limitations. First, the waitee must be defined prior to the waiter job
|
|
(meaning no forward references). Second, if a job is being referenced as a
|
|
waitee, it must have a unique name (no duplicate waitees).
|
|
|
|
.. option:: nice=int
|
|
|
|
Run the job with the given nice value. See man :manpage:`nice(2)`.
|
|
|
|
On Windows, values less than -15 set the process class to "High"; -1 through
|
|
-15 set "Above Normal"; 1 through 15 "Below Normal"; and above 15 "Idle"
|
|
priority class.
|
|
|
|
.. option:: prio=int
|
|
|
|
Set the I/O priority value of this job. Linux limits us to a positive value
|
|
between 0 and 7, with 0 being the highest. See man
|
|
:manpage:`ionice(1)`. Refer to an appropriate manpage for other operating
|
|
systems since meaning of priority may differ.
|
|
|
|
.. option:: prioclass=int
|
|
|
|
Set the I/O priority class. See man :manpage:`ionice(1)`.
|
|
|
|
.. option:: cpumask=int
|
|
|
|
Set the CPU affinity of this job. The parameter given is a bitmask of
|
|
allowed CPU's the job may run on. So if you want the allowed CPUs to be 1
|
|
and 5, you would pass the decimal value of (1 << 1 | 1 << 5), or 34. See man
|
|
:manpage:`sched_setaffinity(2)`. This may not work on all supported
|
|
operating systems or kernel versions. This option doesn't work well for a
|
|
higher CPU count than what you can store in an integer mask, so it can only
|
|
control cpus 1-32. For boxes with larger CPU counts, use
|
|
:option:`cpus_allowed`.
|
|
|
|
.. option:: cpus_allowed=str
|
|
|
|
Controls the same options as :option:`cpumask`, but it allows a text setting
|
|
of the permitted CPUs instead. So to use CPUs 1 and 5, you would specify
|
|
``cpus_allowed=1,5``. This options also allows a range of CPUs. Say you
|
|
wanted a binding to CPUs 1, 5, and 8-15, you would set
|
|
``cpus_allowed=1,5,8-15``.
|
|
|
|
.. option:: cpus_allowed_policy=str
|
|
|
|
Set the policy of how fio distributes the CPUs specified by
|
|
:option:`cpus_allowed` or cpumask. Two policies are supported:
|
|
|
|
**shared**
|
|
All jobs will share the CPU set specified.
|
|
**split**
|
|
Each job will get a unique CPU from the CPU set.
|
|
|
|
**shared** is the default behaviour, if the option isn't specified. If
|
|
**split** is specified, then fio will will assign one cpu per job. If not
|
|
enough CPUs are given for the jobs listed, then fio will roundrobin the CPUs
|
|
in the set.
|
|
|
|
.. option:: numa_cpu_nodes=str
|
|
|
|
Set this job running on specified NUMA nodes' CPUs. The arguments allow
|
|
comma delimited list of cpu numbers, A-B ranges, or `all`. Note, to enable
|
|
numa options support, fio must be built on a system with libnuma-dev(el)
|
|
installed.
|
|
|
|
.. option:: numa_mem_policy=str
|
|
|
|
Set this job's memory policy and corresponding NUMA nodes. Format of the
|
|
arguments::
|
|
|
|
<mode>[:<nodelist>]
|
|
|
|
``mode`` is one of the following memory policy: ``default``, ``prefer``,
|
|
``bind``, ``interleave``, ``local`` For ``default`` and ``local`` memory
|
|
policy, no node is needed to be specified. For ``prefer``, only one node is
|
|
allowed. For ``bind`` and ``interleave``, it allow comma delimited list of
|
|
numbers, A-B ranges, or `all`.
|
|
|
|
.. option:: cgroup=str
|
|
|
|
Add job to this control group. If it doesn't exist, it will be created. The
|
|
system must have a mounted cgroup blkio mount point for this to work. If
|
|
your system doesn't have it mounted, you can do so with::
|
|
|
|
# mount -t cgroup -o blkio none /cgroup
|
|
|
|
.. option:: cgroup_weight=int
|
|
|
|
Set the weight of the cgroup to this value. See the documentation that comes
|
|
with the kernel, allowed values are in the range of 100..1000.
|
|
|
|
.. option:: cgroup_nodelete=bool
|
|
|
|
Normally fio will delete the cgroups it has created after the job
|
|
completion. To override this behavior and to leave cgroups around after the
|
|
job completion, set ``cgroup_nodelete=1``. This can be useful if one wants
|
|
to inspect various cgroup files after job completion. Default: false.
|
|
|
|
.. option:: flow_id=int
|
|
|
|
The ID of the flow. If not specified, it defaults to being a global
|
|
flow. See :option:`flow`.
|
|
|
|
.. option:: flow=int
|
|
|
|
Weight in token-based flow control. If this value is used, then there is a
|
|
'flow counter' which is used to regulate the proportion of activity between
|
|
two or more jobs. Fio attempts to keep this flow counter near zero. The
|
|
``flow`` parameter stands for how much should be added or subtracted to the
|
|
flow counter on each iteration of the main I/O loop. That is, if one job has
|
|
``flow=8`` and another job has ``flow=-1``, then there will be a roughly 1:8
|
|
ratio in how much one runs vs the other.
|
|
|
|
.. option:: flow_watermark=int
|
|
|
|
The maximum value that the absolute value of the flow counter is allowed to
|
|
reach before the job must wait for a lower value of the counter.
|
|
|
|
.. option:: flow_sleep=int
|
|
|
|
The period of time, in microseconds, to wait after the flow watermark has
|
|
been exceeded before retrying operations.
|
|
|
|
.. option:: stonewall, wait_for_previous
|
|
|
|
Wait for preceding jobs in the job file to exit, before starting this
|
|
one. Can be used to insert serialization points in the job file. A stone
|
|
wall also implies starting a new reporting group, see
|
|
:option:`group_reporting`.
|
|
|
|
.. option:: exitall
|
|
|
|
When one job finishes, terminate the rest. The default is to wait for each
|
|
job to finish, sometimes that is not the desired action.
|
|
|
|
.. option:: exec_prerun=str
|
|
|
|
Before running this job, issue the command specified through
|
|
:manpage:`system(3)`. Output is redirected in a file called
|
|
:file:`jobname.prerun.txt`.
|
|
|
|
.. option:: exec_postrun=str
|
|
|
|
After the job completes, issue the command specified though
|
|
:manpage:`system(3)`. Output is redirected in a file called
|
|
:file:`jobname.postrun.txt`.
|
|
|
|
.. option:: uid=int
|
|
|
|
Instead of running as the invoking user, set the user ID to this value
|
|
before the thread/process does any work.
|
|
|
|
.. option:: gid=int
|
|
|
|
Set group ID, see :option:`uid`.
|
|
|
|
|
|
Verification
|
|
~~~~~~~~~~~~
|
|
|
|
.. option:: verify_only
|
|
|
|
Do not perform specified workload, only verify data still matches previous
|
|
invocation of this workload. This option allows one to check data multiple
|
|
times at a later date without overwriting it. This option makes sense only
|
|
for workloads that write data, and does not support workloads with the
|
|
:option:`time_based` option set.
|
|
|
|
.. option:: do_verify=bool
|
|
|
|
Run the verify phase after a write phase. Only valid if :option:`verify` is
|
|
set. Default: true.
|
|
|
|
.. option:: verify=str
|
|
|
|
If writing to a file, fio can verify the file contents after each iteration
|
|
of the job. Each verification method also implies verification of special
|
|
header, which is written to the beginning of each block. This header also
|
|
includes meta information, like offset of the block, block number, timestamp
|
|
when block was written, etc. :option:`verify` can be combined with
|
|
:option:`verify_pattern` option. The allowed values are:
|
|
|
|
**md5**
|
|
Use an md5 sum of the data area and store it in the header of
|
|
each block.
|
|
|
|
**crc64**
|
|
Use an experimental crc64 sum of the data area and store it in the
|
|
header of each block.
|
|
|
|
**crc32c**
|
|
Use a crc32c sum of the data area and store it in the header of each
|
|
block.
|
|
|
|
**crc32c-intel**
|
|
Use hardware assisted crc32c calculation provided on SSE4.2 enabled
|
|
processors. Falls back to regular software crc32c, if not supported
|
|
by the system.
|
|
|
|
**crc32**
|
|
Use a crc32 sum of the data area and store it in the header of each
|
|
block.
|
|
|
|
**crc16**
|
|
Use a crc16 sum of the data area and store it in the header of each
|
|
block.
|
|
|
|
**crc7**
|
|
Use a crc7 sum of the data area and store it in the header of each
|
|
block.
|
|
|
|
**xxhash**
|
|
Use xxhash as the checksum function. Generally the fastest software
|
|
checksum that fio supports.
|
|
|
|
**sha512**
|
|
Use sha512 as the checksum function.
|
|
|
|
**sha256**
|
|
Use sha256 as the checksum function.
|
|
|
|
**sha1**
|
|
Use optimized sha1 as the checksum function.
|
|
|
|
**sha3-224**
|
|
Use optimized sha3-224 as the checksum function.
|
|
|
|
**sha3-256**
|
|
Use optimized sha3-256 as the checksum function.
|
|
|
|
**sha3-384**
|
|
Use optimized sha3-384 as the checksum function.
|
|
|
|
**sha3-512**
|
|
Use optimized sha3-512 as the checksum function.
|
|
|
|
**meta**
|
|
This option is deprecated, since now meta information is included in
|
|
generic verification header and meta verification happens by
|
|
default. For detailed information see the description of the
|
|
:option:`verify` setting. This option is kept because of
|
|
compatibility's sake with old configurations. Do not use it.
|
|
|
|
**pattern**
|
|
Verify a strict pattern. Normally fio includes a header with some
|
|
basic information and checksumming, but if this option is set, only
|
|
the specific pattern set with :option:`verify_pattern` is verified.
|
|
|
|
**null**
|
|
Only pretend to verify. Useful for testing internals with
|
|
:option:`ioengine` `=null`, not for much else.
|
|
|
|
This option can be used for repeated burn-in tests of a system to make sure
|
|
that the written data is also correctly read back. If the data direction
|
|
given is a read or random read, fio will assume that it should verify a
|
|
previously written file. If the data direction includes any form of write,
|
|
the verify will be of the newly written data.
|
|
|
|
.. option:: verifysort=bool
|
|
|
|
If true, fio will sort written verify blocks when it deems it faster to read
|
|
them back in a sorted manner. This is often the case when overwriting an
|
|
existing file, since the blocks are already laid out in the file system. You
|
|
can ignore this option unless doing huge amounts of really fast I/O where
|
|
the red-black tree sorting CPU time becomes significant. Default: true.
|
|
|
|
.. option:: verifysort_nr=int
|
|
|
|
Pre-load and sort verify blocks for a read workload.
|
|
|
|
.. option:: verify_offset=int
|
|
|
|
Swap the verification header with data somewhere else in the block before
|
|
writing. It is swapped back before verifying.
|
|
|
|
.. option:: verify_interval=int
|
|
|
|
Write the verification header at a finer granularity than the
|
|
:option:`blocksize`. It will be written for chunks the size of
|
|
``verify_interval``. :option:`blocksize` should divide this evenly.
|
|
|
|
.. option:: verify_pattern=str
|
|
|
|
If set, fio will fill the I/O buffers with this pattern. Fio defaults to
|
|
filling with totally random bytes, but sometimes it's interesting to fill
|
|
with a known pattern for I/O verification purposes. Depending on the width
|
|
of the pattern, fio will fill 1/2/3/4 bytes of the buffer at the time(it can
|
|
be either a decimal or a hex number). The ``verify_pattern`` if larger than
|
|
a 32-bit quantity has to be a hex number that starts with either "0x" or
|
|
"0X". Use with :option:`verify`. Also, ``verify_pattern`` supports %o
|
|
format, which means that for each block offset will be written and then
|
|
verified back, e.g.::
|
|
|
|
verify_pattern=%o
|
|
|
|
Or use combination of everything::
|
|
|
|
verify_pattern=0xff%o"abcd"-12
|
|
|
|
.. option:: verify_fatal=bool
|
|
|
|
Normally fio will keep checking the entire contents before quitting on a
|
|
block verification failure. If this option is set, fio will exit the job on
|
|
the first observed failure. Default: false.
|
|
|
|
.. option:: verify_dump=bool
|
|
|
|
If set, dump the contents of both the original data block and the data block
|
|
we read off disk to files. This allows later analysis to inspect just what
|
|
kind of data corruption occurred. Off by default.
|
|
|
|
.. option:: verify_async=int
|
|
|
|
Fio will normally verify I/O inline from the submitting thread. This option
|
|
takes an integer describing how many async offload threads to create for I/O
|
|
verification instead, causing fio to offload the duty of verifying I/O
|
|
contents to one or more separate threads. If using this offload option, even
|
|
sync I/O engines can benefit from using an :option:`iodepth` setting higher
|
|
than 1, as it allows them to have I/O in flight while verifies are running.
|
|
|
|
.. option:: verify_async_cpus=str
|
|
|
|
Tell fio to set the given CPU affinity on the async I/O verification
|
|
threads. See :option:`cpus_allowed` for the format used.
|
|
|
|
.. option:: verify_backlog=int
|
|
|
|
Fio will normally verify the written contents of a job that utilizes verify
|
|
once that job has completed. In other words, everything is written then
|
|
everything is read back and verified. You may want to verify continually
|
|
instead for a variety of reasons. Fio stores the meta data associated with
|
|
an I/O block in memory, so for large verify workloads, quite a bit of memory
|
|
would be used up holding this meta data. If this option is enabled, fio will
|
|
write only N blocks before verifying these blocks.
|
|
|
|
.. option:: verify_backlog_batch=int
|
|
|
|
Control how many blocks fio will verify if :option:`verify_backlog` is
|
|
set. If not set, will default to the value of :option:`verify_backlog`
|
|
(meaning the entire queue is read back and verified). If
|
|
``verify_backlog_batch`` is less than :option:`verify_backlog` then not all
|
|
blocks will be verified, if ``verify_backlog_batch`` is larger than
|
|
:option:`verify_backlog`, some blocks will be verified more than once.
|
|
|
|
.. option:: verify_state_save=bool
|
|
|
|
When a job exits during the write phase of a verify workload, save its
|
|
current state. This allows fio to replay up until that point, if the verify
|
|
state is loaded for the verify read phase. The format of the filename is,
|
|
roughly::
|
|
|
|
<type>-<jobname>-<jobindex>-verify.state.
|
|
|
|
<type> is "local" for a local run, "sock" for a client/server socket
|
|
connection, and "ip" (192.168.0.1, for instance) for a networked
|
|
client/server connection.
|
|
|
|
.. option:: verify_state_load=bool
|
|
|
|
If a verify termination trigger was used, fio stores the current write state
|
|
of each thread. This can be used at verification time so that fio knows how
|
|
far it should verify. Without this information, fio will run a full
|
|
verification pass, according to the settings in the job file used.
|
|
|
|
.. option:: trim_percentage=int
|
|
|
|
Number of verify blocks to discard/trim.
|
|
|
|
.. option:: trim_verify_zero=bool
|
|
|
|
Verify that trim/discarded blocks are returned as zeroes.
|
|
|
|
.. option:: trim_backlog=int
|
|
|
|
Verify that trim/discarded blocks are returned as zeroes.
|
|
|
|
.. option:: trim_backlog_batch=int
|
|
|
|
Trim this number of I/O blocks.
|
|
|
|
.. option:: experimental_verify=bool
|
|
|
|
Enable experimental verification.
|
|
|
|
|
|
Steady state
|
|
~~~~~~~~~~~~
|
|
|
|
.. option:: steadystate=str:float, ss=str:float
|
|
|
|
Define the criterion and limit for assessing steady state performance. The
|
|
first parameter designates the criterion whereas the second parameter sets
|
|
the threshold. When the criterion falls below the threshold for the
|
|
specified duration, the job will stop. For example, `iops_slope:0.1%` will
|
|
direct fio to terminate the job when the least squares regression slope
|
|
falls below 0.1% of the mean IOPS. If :option:`group_reporting` is enabled
|
|
this will apply to all jobs in the group. Below is the list of available
|
|
steady state assessment criteria. All assessments are carried out using only
|
|
data from the rolling collection window. Threshold limits can be expressed
|
|
as a fixed value or as a percentage of the mean in the collection window.
|
|
|
|
**iops**
|
|
Collect IOPS data. Stop the job if all individual IOPS measurements
|
|
are within the specified limit of the mean IOPS (e.g., ``iops:2``
|
|
means that all individual IOPS values must be within 2 of the mean,
|
|
whereas ``iops:0.2%`` means that all individual IOPS values must be
|
|
within 0.2% of the mean IOPS to terminate the job).
|
|
|
|
**iops_slope**
|
|
Collect IOPS data and calculate the least squares regression
|
|
slope. Stop the job if the slope falls below the specified limit.
|
|
|
|
**bw**
|
|
Collect bandwidth data. Stop the job if all individual bandwidth
|
|
measurements are within the specified limit of the mean bandwidth.
|
|
|
|
**bw_slope**
|
|
Collect bandwidth data and calculate the least squares regression
|
|
slope. Stop the job if the slope falls below the specified limit.
|
|
|
|
.. option:: steadystate_duration=time, ss_dur=time
|
|
|
|
A rolling window of this duration will be used to judge whether steady state
|
|
has been reached. Data will be collected once per second. The default is 0
|
|
which disables steady state detection. When the unit is omitted, the
|
|
value is given in seconds.
|
|
|
|
.. option:: steadystate_ramp_time=time, ss_ramp=time
|
|
|
|
Allow the job to run for the specified duration before beginning data
|
|
collection for checking the steady state job termination criterion. The
|
|
default is 0. When the unit is omitted, the value is given in seconds.
|
|
|
|
|
|
Measurements and reporting
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
.. option:: per_job_logs=bool
|
|
|
|
If set, this generates bw/clat/iops log with per file private filenames. If
|
|
not set, jobs with identical names will share the log filename. Default:
|
|
true.
|
|
|
|
.. option:: group_reporting
|
|
|
|
It may sometimes be interesting to display statistics for groups of jobs as
|
|
a whole instead of for each individual job. This is especially true if
|
|
:option:`numjobs` is used; looking at individual thread/process output
|
|
quickly becomes unwieldy. To see the final report per-group instead of
|
|
per-job, use :option:`group_reporting`. Jobs in a file will be part of the
|
|
same reporting group, unless if separated by a :option:`stonewall`, or by
|
|
using :option:`new_group`.
|
|
|
|
.. option:: new_group
|
|
|
|
Start a new reporting group. See: :option:`group_reporting`. If not given,
|
|
all jobs in a file will be part of the same reporting group, unless
|
|
separated by a :option:`stonewall`.
|
|
|
|
.. option:: stats
|
|
|
|
By default, fio collects and shows final output results for all jobs
|
|
that run. If this option is set to 0, then fio will ignore it in
|
|
the final stat output.
|
|
|
|
.. option:: write_bw_log=str
|
|
|
|
If given, write a bandwidth log for this job. Can be used to store data of
|
|
the bandwidth of the jobs in their lifetime. The included
|
|
:command:`fio_generate_plots` script uses :command:`gnuplot` to turn these
|
|
text files into nice graphs. See :option:`write_lat_log` for behaviour of
|
|
given filename. For this option, the postfix is :file:`_bw.x.log`, where `x`
|
|
is the index of the job (`1..N`, where `N` is the number of jobs). If
|
|
:option:`per_job_logs` is false, then the filename will not include the job
|
|
index. See `Log File Formats`_.
|
|
|
|
.. option:: write_lat_log=str
|
|
|
|
Same as :option:`write_bw_log`, except that this option stores I/O
|
|
submission, completion, and total latencies instead. If no filename is given
|
|
with this option, the default filename of :file:`jobname_type.log` is
|
|
used. Even if the filename is given, fio will still append the type of
|
|
log. So if one specifies::
|
|
|
|
write_lat_log=foo
|
|
|
|
The actual log names will be :file:`foo_slat.x.log`, :file:`foo_clat.x.log`,
|
|
and :file:`foo_lat.x.log`, where `x` is the index of the job (1..N, where N
|
|
is the number of jobs). This helps :command:`fio_generate_plot` find the
|
|
logs automatically. If :option:`per_job_logs` is false, then the filename
|
|
will not include the job index. See `Log File Formats`_.
|
|
|
|
.. option:: write_hist_log=str
|
|
|
|
Same as :option:`write_lat_log`, but writes I/O completion latency
|
|
histograms. If no filename is given with this option, the default filename
|
|
of :file:`jobname_clat_hist.x.log` is used, where `x` is the index of the
|
|
job (1..N, where `N` is the number of jobs). Even if the filename is given,
|
|
fio will still append the type of log. If :option:`per_job_logs` is false,
|
|
then the filename will not include the job index. See `Log File Formats`_.
|
|
|
|
.. option:: write_iops_log=str
|
|
|
|
Same as :option:`write_bw_log`, but writes IOPS. If no filename is given
|
|
with this option, the default filename of :file:`jobname_type.x.log` is
|
|
used,where `x` is the index of the job (1..N, where `N` is the number of
|
|
jobs). Even if the filename is given, fio will still append the type of
|
|
log. If :option:`per_job_logs` is false, then the filename will not include
|
|
the job index. See `Log File Formats`_.
|
|
|
|
.. option:: log_avg_msec=int
|
|
|
|
By default, fio will log an entry in the iops, latency, or bw log for every
|
|
I/O that completes. When writing to the disk log, that can quickly grow to a
|
|
very large size. Setting this option makes fio average the each log entry
|
|
over the specified period of time, reducing the resolution of the log. See
|
|
:option:`log_max_value` as well. Defaults to 0, logging all entries.
|
|
|
|
.. option:: log_hist_msec=int
|
|
|
|
Same as :option:`log_avg_msec`, but logs entries for completion latency
|
|
histograms. Computing latency percentiles from averages of intervals using
|
|
:option:`log_avg_msec` is inaccurate. Setting this option makes fio log
|
|
histogram entries over the specified period of time, reducing log sizes for
|
|
high IOPS devices while retaining percentile accuracy. See
|
|
:option:`log_hist_coarseness` as well. Defaults to 0, meaning histogram
|
|
logging is disabled.
|
|
|
|
.. option:: log_hist_coarseness=int
|
|
|
|
Integer ranging from 0 to 6, defining the coarseness of the resolution of
|
|
the histogram logs enabled with :option:`log_hist_msec`. For each increment
|
|
in coarseness, fio outputs half as many bins. Defaults to 0, for which
|
|
histogram logs contain 1216 latency bins. See `Log File Formats`_.
|
|
|
|
.. option:: log_max_value=bool
|
|
|
|
If :option:`log_avg_msec` is set, fio logs the average over that window. If
|
|
you instead want to log the maximum value, set this option to 1. Defaults to
|
|
0, meaning that averaged values are logged.
|
|
|
|
.. option:: log_offset=int
|
|
|
|
If this is set, the iolog options will include the byte offset for the I/O
|
|
entry as well as the other data values.
|
|
|
|
.. option:: log_compression=int
|
|
|
|
If this is set, fio will compress the I/O logs as it goes, to keep the
|
|
memory footprint lower. When a log reaches the specified size, that chunk is
|
|
removed and compressed in the background. Given that I/O logs are fairly
|
|
highly compressible, this yields a nice memory savings for longer runs. The
|
|
downside is that the compression will consume some background CPU cycles, so
|
|
it may impact the run. This, however, is also true if the logging ends up
|
|
consuming most of the system memory. So pick your poison. The I/O logs are
|
|
saved normally at the end of a run, by decompressing the chunks and storing
|
|
them in the specified log file. This feature depends on the availability of
|
|
zlib.
|
|
|
|
.. option:: log_compression_cpus=str
|
|
|
|
Define the set of CPUs that are allowed to handle online log compression for
|
|
the I/O jobs. This can provide better isolation between performance
|
|
sensitive jobs, and background compression work.
|
|
|
|
.. option:: log_store_compressed=bool
|
|
|
|
If set, fio will store the log files in a compressed format. They can be
|
|
decompressed with fio, using the :option:`--inflate-log` command line
|
|
parameter. The files will be stored with a :file:`.fz` suffix.
|
|
|
|
.. option:: log_unix_epoch=bool
|
|
|
|
If set, fio will log Unix timestamps to the log files produced by enabling
|
|
write_type_log for each log type, instead of the default zero-based
|
|
timestamps.
|
|
|
|
.. option:: block_error_percentiles=bool
|
|
|
|
If set, record errors in trim block-sized units from writes and trims and
|
|
output a histogram of how many trims it took to get to errors, and what kind
|
|
of error was encountered.
|
|
|
|
.. option:: bwavgtime=int
|
|
|
|
Average the calculated bandwidth over the given time. Value is specified in
|
|
milliseconds. If the job also does bandwidth logging through
|
|
:option:`write_bw_log`, then the minimum of this option and
|
|
:option:`log_avg_msec` will be used. Default: 500ms.
|
|
|
|
.. option:: iopsavgtime=int
|
|
|
|
Average the calculated IOPS over the given time. Value is specified in
|
|
milliseconds. If the job also does IOPS logging through
|
|
:option:`write_iops_log`, then the minimum of this option and
|
|
:option:`log_avg_msec` will be used. Default: 500ms.
|
|
|
|
.. option:: disk_util=bool
|
|
|
|
Generate disk utilization statistics, if the platform supports it.
|
|
Default: true.
|
|
|
|
.. option:: disable_lat=bool
|
|
|
|
Disable measurements of total latency numbers. Useful only for cutting back
|
|
the number of calls to :manpage:`gettimeofday(2)`, as that does impact
|
|
performance at really high IOPS rates. Note that to really get rid of a
|
|
large amount of these calls, this option must be used with
|
|
:option:`disable_slat` and :option:`disable_bw_measurement` as well.
|
|
|
|
.. option:: disable_clat=bool
|
|
|
|
Disable measurements of completion latency numbers. See
|
|
:option:`disable_lat`.
|
|
|
|
.. option:: disable_slat=bool
|
|
|
|
Disable measurements of submission latency numbers. See
|
|
:option:`disable_slat`.
|
|
|
|
.. option:: disable_bw_measurement=bool, disable_bw=bool
|
|
|
|
Disable measurements of throughput/bandwidth numbers. See
|
|
:option:`disable_lat`.
|
|
|
|
.. option:: clat_percentiles=bool
|
|
|
|
Enable the reporting of percentiles of completion latencies.
|
|
|
|
.. option:: percentile_list=float_list
|
|
|
|
Overwrite the default list of percentiles for completion latencies and the
|
|
block error histogram. Each number is a floating number in the range
|
|
(0,100], and the maximum length of the list is 20. Use ``:`` to separate the
|
|
numbers, and list the numbers in ascending order. For example,
|
|
``--percentile_list=99.5:99.9`` will cause fio to report the values of
|
|
completion latency below which 99.5% and 99.9% of the observed latencies
|
|
fell, respectively.
|
|
|
|
|
|
Error handling
|
|
~~~~~~~~~~~~~~
|
|
|
|
.. option:: exitall_on_error
|
|
|
|
When one job finishes in error, terminate the rest. The default is to wait
|
|
for each job to finish.
|
|
|
|
.. option:: continue_on_error=str
|
|
|
|
Normally fio will exit the job on the first observed failure. If this option
|
|
is set, fio will continue the job when there is a 'non-fatal error' (EIO or
|
|
EILSEQ) until the runtime is exceeded or the I/O size specified is
|
|
completed. If this option is used, there are two more stats that are
|
|
appended, the total error count and the first error. The error field given
|
|
in the stats is the first error that was hit during the run.
|
|
|
|
The allowed values are:
|
|
|
|
**none**
|
|
Exit on any I/O or verify errors.
|
|
|
|
**read**
|
|
Continue on read errors, exit on all others.
|
|
|
|
**write**
|
|
Continue on write errors, exit on all others.
|
|
|
|
**io**
|
|
Continue on any I/O error, exit on all others.
|
|
|
|
**verify**
|
|
Continue on verify errors, exit on all others.
|
|
|
|
**all**
|
|
Continue on all errors.
|
|
|
|
**0**
|
|
Backward-compatible alias for 'none'.
|
|
|
|
**1**
|
|
Backward-compatible alias for 'all'.
|
|
|
|
.. option:: ignore_error=str
|
|
|
|
Sometimes you want to ignore some errors during test in that case you can
|
|
specify error list for each error type.
|
|
``ignore_error=READ_ERR_LIST,WRITE_ERR_LIST,VERIFY_ERR_LIST`` errors for
|
|
given error type is separated with ':'. Error may be symbol ('ENOSPC',
|
|
'ENOMEM') or integer. Example::
|
|
|
|
ignore_error=EAGAIN,ENOSPC:122
|
|
|
|
This option will ignore EAGAIN from READ, and ENOSPC and 122(EDQUOT) from
|
|
WRITE.
|
|
|
|
.. option:: error_dump=bool
|
|
|
|
If set dump every error even if it is non fatal, true by default. If
|
|
disabled only fatal error will be dumped.
|
|
|
|
Running predefined workloads
|
|
----------------------------
|
|
|
|
Fio includes predefined profiles that mimic the I/O workloads generated by
|
|
other tools.
|
|
|
|
.. option:: profile=str
|
|
|
|
The predefined workload to run. Current profiles are:
|
|
|
|
**tiobench**
|
|
Threaded I/O bench (tiotest/tiobench) like workload.
|
|
|
|
**act**
|
|
Aerospike Certification Tool (ACT) like workload.
|
|
|
|
To view a profile's additional options use :option:`--cmdhelp` after specifying
|
|
the profile. For example::
|
|
|
|
$ fio --profile=act --cmdhelp
|
|
|
|
Act profile options
|
|
~~~~~~~~~~~~~~~~~~~
|
|
|
|
.. option:: device-names=str
|
|
:noindex:
|
|
|
|
Devices to use.
|
|
|
|
.. option:: load=int
|
|
:noindex:
|
|
|
|
ACT load multiplier. Default: 1.
|
|
|
|
.. option:: test-duration=time
|
|
:noindex:
|
|
|
|
How long the entire test takes to run. Default: 24h.
|
|
|
|
.. option:: threads-per-queue=int
|
|
:noindex:
|
|
|
|
Number of read IO threads per device. Default: 8.
|
|
|
|
.. option:: read-req-num-512-blocks=int
|
|
:noindex:
|
|
|
|
Number of 512B blocks to read at the time. Default: 3.
|
|
|
|
.. option:: large-block-op-kbytes=int
|
|
:noindex:
|
|
|
|
Size of large block ops in KiB (writes). Default: 131072.
|
|
|
|
.. option:: prep
|
|
:noindex:
|
|
|
|
Set to run ACT prep phase.
|
|
|
|
Tiobench profile options
|
|
~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
.. option:: size=str
|
|
:noindex:
|
|
|
|
Size in MiB
|
|
|
|
.. option:: block=int
|
|
:noindex:
|
|
|
|
Block size in bytes. Default: 4096.
|
|
|
|
.. option:: numruns=int
|
|
:noindex:
|
|
|
|
Number of runs.
|
|
|
|
.. option:: dir=str
|
|
:noindex:
|
|
|
|
Test directory.
|
|
|
|
.. option:: threads=int
|
|
:noindex:
|
|
|
|
Number of threads.
|
|
|
|
Interpreting the output
|
|
-----------------------
|
|
|
|
Fio spits out a lot of output. While running, fio will display the status of the
|
|
jobs created. An example of that would be::
|
|
|
|
Jobs: 1 (f=1): [_(1),M(1)][24.8%][r=20.5MiB/s,w=23.5MiB/s][r=82,w=94 IOPS][eta 01m:31s]
|
|
|
|
The characters inside the square brackets denote the current status of each
|
|
thread. The possible values (in typical life cycle order) are:
|
|
|
|
+------+-----+-----------------------------------------------------------+
|
|
| Idle | Run | |
|
|
+======+=====+===========================================================+
|
|
| P | | Thread setup, but not started. |
|
|
+------+-----+-----------------------------------------------------------+
|
|
| C | | Thread created. |
|
|
+------+-----+-----------------------------------------------------------+
|
|
| I | | Thread initialized, waiting or generating necessary data. |
|
|
+------+-----+-----------------------------------------------------------+
|
|
| | p | Thread running pre-reading file(s). |
|
|
+------+-----+-----------------------------------------------------------+
|
|
| | R | Running, doing sequential reads. |
|
|
+------+-----+-----------------------------------------------------------+
|
|
| | r | Running, doing random reads. |
|
|
+------+-----+-----------------------------------------------------------+
|
|
| | W | Running, doing sequential writes. |
|
|
+------+-----+-----------------------------------------------------------+
|
|
| | w | Running, doing random writes. |
|
|
+------+-----+-----------------------------------------------------------+
|
|
| | M | Running, doing mixed sequential reads/writes. |
|
|
+------+-----+-----------------------------------------------------------+
|
|
| | m | Running, doing mixed random reads/writes. |
|
|
+------+-----+-----------------------------------------------------------+
|
|
| | F | Running, currently waiting for :manpage:`fsync(2)` |
|
|
+------+-----+-----------------------------------------------------------+
|
|
| | V | Running, doing verification of written data. |
|
|
+------+-----+-----------------------------------------------------------+
|
|
| E | | Thread exited, not reaped by main thread yet. |
|
|
+------+-----+-----------------------------------------------------------+
|
|
| _ | | Thread reaped, or |
|
|
+------+-----+-----------------------------------------------------------+
|
|
| X | | Thread reaped, exited with an error. |
|
|
+------+-----+-----------------------------------------------------------+
|
|
| K | | Thread reaped, exited due to signal. |
|
|
+------+-----+-----------------------------------------------------------+
|
|
|
|
Fio will condense the thread string as not to take up more space on the command
|
|
line as is needed. For instance, if you have 10 readers and 10 writers running,
|
|
the output would look like this::
|
|
|
|
Jobs: 20 (f=20): [R(10),W(10)][4.0%][r=20.5MiB/s,w=23.5MiB/s][r=82,w=94 IOPS][eta 57m:36s]
|
|
|
|
Fio will still maintain the ordering, though. So the above means that jobs 1..10
|
|
are readers, and 11..20 are writers.
|
|
|
|
The other values are fairly self explanatory -- number of threads currently
|
|
running and doing I/O, the number of currently open files (f=), the rate of I/O
|
|
since last check (read speed listed first, then write speed and optionally trim
|
|
speed), and the estimated completion percentage and time for the current
|
|
running group. It's impossible to estimate runtime of the following groups (if
|
|
any). Note that the string is displayed in order, so it's possible to tell which
|
|
of the jobs are currently doing what. The first character is the first job
|
|
defined in the job file, and so forth.
|
|
|
|
When fio is done (or interrupted by :kbd:`ctrl-c`), it will show the data for
|
|
each thread, group of threads, and disks in that order. For each data direction,
|
|
the output looks like::
|
|
|
|
Client1 (g=0): err= 0:
|
|
write: io= 32MiB, bw= 666KiB/s, iops=89 , runt= 50320msec
|
|
slat (msec): min= 0, max= 136, avg= 0.03, stdev= 1.92
|
|
clat (msec): min= 0, max= 631, avg=48.50, stdev=86.82
|
|
bw (KiB/s) : min= 0, max= 1196, per=51.00%, avg=664.02, stdev=681.68
|
|
cpu : usr=1.49%, sys=0.25%, ctx=7969, majf=0, minf=17
|
|
IO depths : 1=0.1%, 2=0.3%, 4=0.5%, 8=99.0%, 16=0.0%, 32=0.0%, >32=0.0%
|
|
submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
|
|
complete : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
|
|
issued r/w: total=0/32768, short=0/0
|
|
lat (msec): 2=1.6%, 4=0.0%, 10=3.2%, 20=12.8%, 50=38.4%, 100=24.8%,
|
|
lat (msec): 250=15.2%, 500=0.0%, 750=0.0%, 1000=0.0%, >=2048=0.0%
|
|
|
|
The client number is printed, along with the group id and error of that
|
|
thread. Below is the I/O statistics, here for writes. In the order listed, they
|
|
denote:
|
|
|
|
**io**
|
|
Number of megabytes I/O performed.
|
|
|
|
**bw**
|
|
Average bandwidth rate.
|
|
|
|
**iops**
|
|
Average I/Os performed per second.
|
|
|
|
**runt**
|
|
The runtime of that thread.
|
|
|
|
**slat**
|
|
Submission latency (avg being the average, stdev being the standard
|
|
deviation). This is the time it took to submit the I/O. For sync I/O,
|
|
the slat is really the completion latency, since queue/complete is one
|
|
operation there. This value can be in milliseconds or microseconds, fio
|
|
will choose the most appropriate base and print that. In the example
|
|
above, milliseconds is the best scale. Note: in :option:`--minimal` mode
|
|
latencies are always expressed in microseconds.
|
|
|
|
**clat**
|
|
Completion latency. Same names as slat, this denotes the time from
|
|
submission to completion of the I/O pieces. For sync I/O, clat will
|
|
usually be equal (or very close) to 0, as the time from submit to
|
|
complete is basically just CPU time (I/O has already been done, see slat
|
|
explanation).
|
|
|
|
**bw**
|
|
Bandwidth. Same names as the xlat stats, but also includes an
|
|
approximate percentage of total aggregate bandwidth this thread received
|
|
in this group. This last value is only really useful if the threads in
|
|
this group are on the same disk, since they are then competing for disk
|
|
access.
|
|
|
|
**cpu**
|
|
CPU usage. User and system time, along with the number of context
|
|
switches this thread went through, usage of system and user time, and
|
|
finally the number of major and minor page faults. The CPU utilization
|
|
numbers are averages for the jobs in that reporting group, while the
|
|
context and fault counters are summed.
|
|
|
|
**IO depths**
|
|
The distribution of I/O depths over the job life time. The numbers are
|
|
divided into powers of 2, so for example the 16= entries includes depths
|
|
up to that value but higher than the previous entry. In other words, it
|
|
covers the range from 16 to 31.
|
|
|
|
**IO submit**
|
|
How many pieces of I/O were submitting in a single submit call. Each
|
|
entry denotes that amount and below, until the previous entry -- e.g.,
|
|
8=100% mean that we submitted anywhere in between 5-8 I/Os per submit
|
|
call.
|
|
|
|
**IO complete**
|
|
Like the above submit number, but for completions instead.
|
|
|
|
**IO issued**
|
|
The number of read/write requests issued, and how many of them were
|
|
short.
|
|
|
|
**IO latencies**
|
|
The distribution of I/O completion latencies. This is the time from when
|
|
I/O leaves fio and when it gets completed. The numbers follow the same
|
|
pattern as the I/O depths, meaning that 2=1.6% means that 1.6% of the
|
|
I/O completed within 2 msecs, 20=12.8% means that 12.8% of the I/O took
|
|
more than 10 msecs, but less than (or equal to) 20 msecs.
|
|
|
|
After each client has been listed, the group statistics are printed. They
|
|
will look like this::
|
|
|
|
Run status group 0 (all jobs):
|
|
READ: io=64MB, aggrb=22178, minb=11355, maxb=11814, mint=2840msec, maxt=2955msec
|
|
WRITE: io=64MB, aggrb=1302, minb=666, maxb=669, mint=50093msec, maxt=50320msec
|
|
|
|
For each data direction, it prints:
|
|
|
|
**io**
|
|
Number of megabytes I/O performed.
|
|
**aggrb**
|
|
Aggregate bandwidth of threads in this group.
|
|
**minb**
|
|
The minimum average bandwidth a thread saw.
|
|
**maxb**
|
|
The maximum average bandwidth a thread saw.
|
|
**mint**
|
|
The smallest runtime of the threads in that group.
|
|
**maxt**
|
|
The longest runtime of the threads in that group.
|
|
|
|
And finally, the disk statistics are printed. They will look like this::
|
|
|
|
Disk stats (read/write):
|
|
sda: ios=16398/16511, merge=30/162, ticks=6853/819634, in_queue=826487, util=100.00%
|
|
|
|
Each value is printed for both reads and writes, with reads first. The
|
|
numbers denote:
|
|
|
|
**ios**
|
|
Number of I/Os performed by all groups.
|
|
**merge**
|
|
Number of merges I/O the I/O scheduler.
|
|
**ticks**
|
|
Number of ticks we kept the disk busy.
|
|
**io_queue**
|
|
Total time spent in the disk queue.
|
|
**util**
|
|
The disk utilization. A value of 100% means we kept the disk
|
|
busy constantly, 50% would be a disk idling half of the time.
|
|
|
|
It is also possible to get fio to dump the current output while it is running,
|
|
without terminating the job. To do that, send fio the **USR1** signal. You can
|
|
also get regularly timed dumps by using the :option:`--status-interval`
|
|
parameter, or by creating a file in :file:`/tmp` named
|
|
:file:`fio-dump-status`. If fio sees this file, it will unlink it and dump the
|
|
current output status.
|
|
|
|
|
|
Terse output
|
|
------------
|
|
|
|
For scripted usage where you typically want to generate tables or graphs of the
|
|
results, fio can output the results in a semicolon separated format. The format
|
|
is one long line of values, such as::
|
|
|
|
2;card0;0;0;7139336;121836;60004;1;10109;27.932460;116.933948;220;126861;3495.446807;1085.368601;226;126864;3523.635629;1089.012448;24063;99944;50.275485%;59818.274627;5540.657370;7155060;122104;60004;1;8338;29.086342;117.839068;388;128077;5032.488518;1234.785715;391;128085;5061.839412;1236.909129;23436;100928;50.287926%;59964.832030;5644.844189;14.595833%;19.394167%;123706;0;7313;0.1%;0.1%;0.1%;0.1%;0.1%;0.1%;100.0%;0.00%;0.00%;0.00%;0.00%;0.00%;0.00%;0.01%;0.02%;0.05%;0.16%;6.04%;40.40%;52.68%;0.64%;0.01%;0.00%;0.01%;0.00%;0.00%;0.00%;0.00%;0.00%
|
|
A description of this job goes here.
|
|
|
|
The job description (if provided) follows on a second line.
|
|
|
|
To enable terse output, use the :option:`--minimal` command line option. The
|
|
first value is the version of the terse output format. If the output has to be
|
|
changed for some reason, this number will be incremented by 1 to signify that
|
|
change.
|
|
|
|
Split up, the format is as follows:
|
|
|
|
::
|
|
|
|
terse version, fio version, jobname, groupid, error
|
|
|
|
READ status::
|
|
|
|
Total IO (KiB), bandwidth (KiB/sec), IOPS, runtime (msec)
|
|
Submission latency: min, max, mean, stdev (usec)
|
|
Completion latency: min, max, mean, stdev (usec)
|
|
Completion latency percentiles: 20 fields (see below)
|
|
Total latency: min, max, mean, stdev (usec)
|
|
Bw (KiB/s): min, max, aggregate percentage of total, mean, stdev
|
|
|
|
WRITE status:
|
|
|
|
::
|
|
|
|
Total IO (KiB), bandwidth (KiB/sec), IOPS, runtime (msec)
|
|
Submission latency: min, max, mean, stdev (usec)
|
|
Completion latency: min, max, mean, stdev(usec)
|
|
Completion latency percentiles: 20 fields (see below)
|
|
Total latency: min, max, mean, stdev (usec)
|
|
Bw (KiB/s): min, max, aggregate percentage of total, mean, stdev
|
|
|
|
CPU usage::
|
|
|
|
user, system, context switches, major faults, minor faults
|
|
|
|
I/O depths::
|
|
|
|
<=1, 2, 4, 8, 16, 32, >=64
|
|
|
|
I/O latencies microseconds::
|
|
|
|
<=2, 4, 10, 20, 50, 100, 250, 500, 750, 1000
|
|
|
|
I/O latencies milliseconds::
|
|
|
|
<=2, 4, 10, 20, 50, 100, 250, 500, 750, 1000, 2000, >=2000
|
|
|
|
Disk utilization::
|
|
|
|
Disk name, Read ios, write ios,
|
|
Read merges, write merges,
|
|
Read ticks, write ticks,
|
|
Time spent in queue, disk utilization percentage
|
|
|
|
Additional Info (dependent on continue_on_error, default off)::
|
|
|
|
total # errors, first error code
|
|
|
|
Additional Info (dependent on description being set)::
|
|
|
|
Text description
|
|
|
|
Completion latency percentiles can be a grouping of up to 20 sets, so for the
|
|
terse output fio writes all of them. Each field will look like this::
|
|
|
|
1.00%=6112
|
|
|
|
which is the Xth percentile, and the `usec` latency associated with it.
|
|
|
|
For disk utilization, all disks used by fio are shown. So for each disk there
|
|
will be a disk utilization section.
|
|
|
|
|
|
Trace file format
|
|
-----------------
|
|
|
|
There are two trace file format that you can encounter. The older (v1) format is
|
|
unsupported since version 1.20-rc3 (March 2008). It will still be described
|
|
below in case that you get an old trace and want to understand it.
|
|
|
|
In any case the trace is a simple text file with a single action per line.
|
|
|
|
|
|
Trace file format v1
|
|
~~~~~~~~~~~~~~~~~~~~
|
|
|
|
Each line represents a single I/O action in the following format::
|
|
|
|
rw, offset, length
|
|
|
|
where `rw=0/1` for read/write, and the offset and length entries being in bytes.
|
|
|
|
This format is not supported in fio versions => 1.20-rc3.
|
|
|
|
|
|
Trace file format v2
|
|
~~~~~~~~~~~~~~~~~~~~
|
|
|
|
The second version of the trace file format was added in fio version 1.17. It
|
|
allows to access more then one file per trace and has a bigger set of possible
|
|
file actions.
|
|
|
|
The first line of the trace file has to be::
|
|
|
|
fio version 2 iolog
|
|
|
|
Following this can be lines in two different formats, which are described below.
|
|
|
|
The file management format::
|
|
|
|
filename action
|
|
|
|
The filename is given as an absolute path. The action can be one of these:
|
|
|
|
**add**
|
|
Add the given filename to the trace.
|
|
**open**
|
|
Open the file with the given filename. The filename has to have
|
|
been added with the **add** action before.
|
|
**close**
|
|
Close the file with the given filename. The file has to have been
|
|
opened before.
|
|
|
|
|
|
The file I/O action format::
|
|
|
|
filename action offset length
|
|
|
|
The `filename` is given as an absolute path, and has to have been added and
|
|
opened before it can be used with this format. The `offset` and `length` are
|
|
given in bytes. The `action` can be one of these:
|
|
|
|
**wait**
|
|
Wait for `offset` microseconds. Everything below 100 is discarded.
|
|
The time is relative to the previous `wait` statement.
|
|
**read**
|
|
Read `length` bytes beginning from `offset`.
|
|
**write**
|
|
Write `length` bytes beginning from `offset`.
|
|
**sync**
|
|
:manpage:`fsync(2)` the file.
|
|
**datasync**
|
|
:manpage:`fdatasync(2)` the file.
|
|
**trim**
|
|
Trim the given file from the given `offset` for `length` bytes.
|
|
|
|
CPU idleness profiling
|
|
----------------------
|
|
|
|
In some cases, we want to understand CPU overhead in a test. For example, we
|
|
test patches for the specific goodness of whether they reduce CPU usage.
|
|
Fio implements a balloon approach to create a thread per CPU that runs at idle
|
|
priority, meaning that it only runs when nobody else needs the cpu.
|
|
By measuring the amount of work completed by the thread, idleness of each CPU
|
|
can be derived accordingly.
|
|
|
|
An unit work is defined as touching a full page of unsigned characters. Mean and
|
|
standard deviation of time to complete an unit work is reported in "unit work"
|
|
section. Options can be chosen to report detailed percpu idleness or overall
|
|
system idleness by aggregating percpu stats.
|
|
|
|
|
|
Verification and triggers
|
|
-------------------------
|
|
|
|
Fio is usually run in one of two ways, when data verification is done. The first
|
|
is a normal write job of some sort with verify enabled. When the write phase has
|
|
completed, fio switches to reads and verifies everything it wrote. The second
|
|
model is running just the write phase, and then later on running the same job
|
|
(but with reads instead of writes) to repeat the same I/O patterns and verify
|
|
the contents. Both of these methods depend on the write phase being completed,
|
|
as fio otherwise has no idea how much data was written.
|
|
|
|
With verification triggers, fio supports dumping the current write state to
|
|
local files. Then a subsequent read verify workload can load this state and know
|
|
exactly where to stop. This is useful for testing cases where power is cut to a
|
|
server in a managed fashion, for instance.
|
|
|
|
A verification trigger consists of two things:
|
|
|
|
1) Storing the write state of each job.
|
|
2) Executing a trigger command.
|
|
|
|
The write state is relatively small, on the order of hundreds of bytes to single
|
|
kilobytes. It contains information on the number of completions done, the last X
|
|
completions, etc.
|
|
|
|
A trigger is invoked either through creation ('touch') of a specified file in
|
|
the system, or through a timeout setting. If fio is run with
|
|
:option:`--trigger-file` = :file:`/tmp/trigger-file`, then it will continually
|
|
check for the existence of :file:`/tmp/trigger-file`. When it sees this file, it
|
|
will fire off the trigger (thus saving state, and executing the trigger
|
|
command).
|
|
|
|
For client/server runs, there's both a local and remote trigger. If fio is
|
|
running as a server backend, it will send the job states back to the client for
|
|
safe storage, then execute the remote trigger, if specified. If a local trigger
|
|
is specified, the server will still send back the write state, but the client
|
|
will then execute the trigger.
|
|
|
|
Verification trigger example
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
Lets say we want to run a powercut test on the remote machine 'server'. Our
|
|
write workload is in :file:`write-test.fio`. We want to cut power to 'server' at
|
|
some point during the run, and we'll run this test from the safety or our local
|
|
machine, 'localbox'. On the server, we'll start the fio backend normally::
|
|
|
|
server# fio --server
|
|
|
|
and on the client, we'll fire off the workload::
|
|
|
|
localbox$ fio --client=server --trigger-file=/tmp/my-trigger --trigger-remote="bash -c \"echo b > /proc/sysrq-triger\""
|
|
|
|
We set :file:`/tmp/my-trigger` as the trigger file, and we tell fio to execute::
|
|
|
|
echo b > /proc/sysrq-trigger
|
|
|
|
on the server once it has received the trigger and sent us the write state. This
|
|
will work, but it's not **really** cutting power to the server, it's merely
|
|
abruptly rebooting it. If we have a remote way of cutting power to the server
|
|
through IPMI or similar, we could do that through a local trigger command
|
|
instead. Lets assume we have a script that does IPMI reboot of a given hostname,
|
|
ipmi-reboot. On localbox, we could then have run fio with a local trigger
|
|
instead::
|
|
|
|
localbox$ fio --client=server --trigger-file=/tmp/my-trigger --trigger="ipmi-reboot server"
|
|
|
|
For this case, fio would wait for the server to send us the write state, then
|
|
execute ``ipmi-reboot server`` when that happened.
|
|
|
|
Loading verify state
|
|
~~~~~~~~~~~~~~~~~~~~
|
|
|
|
To load store write state, read verification job file must contain the
|
|
:option:`verify_state_load` option. If that is set, fio will load the previously
|
|
stored state. For a local fio run this is done by loading the files directly,
|
|
and on a client/server run, the server backend will ask the client to send the
|
|
files over and load them from there.
|
|
|
|
|
|
Log File Formats
|
|
----------------
|
|
|
|
Fio supports a variety of log file formats, for logging latencies, bandwidth,
|
|
and IOPS. The logs share a common format, which looks like this:
|
|
|
|
*time* (`msec`), *value*, *data direction*, *offset*
|
|
|
|
Time for the log entry is always in milliseconds. The *value* logged depends
|
|
on the type of log, it will be one of the following:
|
|
|
|
**Latency log**
|
|
Value is latency in usecs
|
|
**Bandwidth log**
|
|
Value is in KiB/sec
|
|
**IOPS log**
|
|
Value is IOPS
|
|
|
|
*Data direction* is one of the following:
|
|
|
|
**0**
|
|
I/O is a READ
|
|
**1**
|
|
I/O is a WRITE
|
|
**2**
|
|
I/O is a TRIM
|
|
|
|
The *offset* is the offset, in bytes, from the start of the file, for that
|
|
particular I/O. The logging of the offset can be toggled with
|
|
:option:`log_offset`.
|
|
|
|
If windowed logging is enabled through :option:`log_avg_msec` then fio doesn't
|
|
log individual I/Os. Instead of logs the average values over the specified period
|
|
of time. Since 'data direction' and 'offset' are per-I/O values, they aren't
|
|
applicable if windowed logging is enabled. If windowed logging is enabled and
|
|
:option:`log_max_value` is set, then fio logs maximum values in that window
|
|
instead of averages.
|
|
|
|
|
|
Client/server
|
|
-------------
|
|
|
|
Normally fio is invoked as a stand-alone application on the machine where the
|
|
I/O workload should be generated. However, the frontend and backend of fio can
|
|
be run separately. Ie the fio server can generate an I/O workload on the "Device
|
|
Under Test" while being controlled from another machine.
|
|
|
|
Start the server on the machine which has access to the storage DUT::
|
|
|
|
fio --server=args
|
|
|
|
where args defines what fio listens to. The arguments are of the form
|
|
``type,hostname`` or ``IP,port``. *type* is either ``ip`` (or ip4) for TCP/IP
|
|
v4, ``ip6`` for TCP/IP v6, or ``sock`` for a local unix domain socket.
|
|
*hostname* is either a hostname or IP address, and *port* is the port to listen
|
|
to (only valid for TCP/IP, not a local socket). Some examples:
|
|
|
|
1) ``fio --server``
|
|
|
|
Start a fio server, listening on all interfaces on the default port (8765).
|
|
|
|
2) ``fio --server=ip:hostname,4444``
|
|
|
|
Start a fio server, listening on IP belonging to hostname and on port 4444.
|
|
|
|
3) ``fio --server=ip6:::1,4444``
|
|
|
|
Start a fio server, listening on IPv6 localhost ::1 and on port 4444.
|
|
|
|
4) ``fio --server=,4444``
|
|
|
|
Start a fio server, listening on all interfaces on port 4444.
|
|
|
|
5) ``fio --server=1.2.3.4``
|
|
|
|
Start a fio server, listening on IP 1.2.3.4 on the default port.
|
|
|
|
6) ``fio --server=sock:/tmp/fio.sock``
|
|
|
|
Start a fio server, listening on the local socket /tmp/fio.sock.
|
|
|
|
Once a server is running, a "client" can connect to the fio server with::
|
|
|
|
fio <local-args> --client=<server> <remote-args> <job file(s)>
|
|
|
|
where `local-args` are arguments for the client where it is running, `server`
|
|
is the connect string, and `remote-args` and `job file(s)` are sent to the
|
|
server. The `server` string follows the same format as it does on the server
|
|
side, to allow IP/hostname/socket and port strings.
|
|
|
|
Fio can connect to multiple servers this way::
|
|
|
|
fio --client=<server1> <job file(s)> --client=<server2> <job file(s)>
|
|
|
|
If the job file is located on the fio server, then you can tell the server to
|
|
load a local file as well. This is done by using :option:`--remote-config` ::
|
|
|
|
fio --client=server --remote-config /path/to/file.fio
|
|
|
|
Then fio will open this local (to the server) job file instead of being passed
|
|
one from the client.
|
|
|
|
If you have many servers (example: 100 VMs/containers), you can input a pathname
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of a file containing host IPs/names as the parameter value for the
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:option:`--client` option. For example, here is an example :file:`host.list`
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file containing 2 hostnames::
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host1.your.dns.domain
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host2.your.dns.domain
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The fio command would then be::
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fio --client=host.list <job file(s)>
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In this mode, you cannot input server-specific parameters or job files -- all
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servers receive the same job file.
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In order to let ``fio --client`` runs use a shared filesystem from multiple
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hosts, ``fio --client`` now prepends the IP address of the server to the
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filename. For example, if fio is using directory :file:`/mnt/nfs/fio` and is
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writing filename :file:`fileio.tmp`, with a :option:`--client` `hostfile`
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containing two hostnames ``h1`` and ``h2`` with IP addresses 192.168.10.120 and
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192.168.10.121, then fio will create two files::
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/mnt/nfs/fio/192.168.10.120.fileio.tmp
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/mnt/nfs/fio/192.168.10.121.fileio.tmp
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