fio

fio(1)                      General Commands Manual                     fio(1)



NAME
       fio - flexible I/O tester

SYNOPSIS
       fio [options] [jobfile]...

DESCRIPTION
       fio is a tool that will spawn a number of threads or processes doing a
       particular type of I/O action as specified by the user.  The typical
       use of fio is to write a job file matching the I/O load one wants to
       simulate.

OPTIONS
       --debug=type
              Enable verbose tracing of various fio actions. May be `all' for
              all types or individual types separated by a comma (eg
              --debug=io,file). `help' will list all available tracing
              options.

       --output=filename
              Write output to filename.

       --runtime=runtime
              Limit run time to runtime seconds.

       --latency-log
              Generate per-job latency logs.

       --bandwidth-log
              Generate per-job bandwidth logs.

       --minimal
              Print statistics in a terse, semicolon-delimited format.

       --append-terse
              Print statistics in selected mode AND terse, semicolon-delimited
              format.

       --version
              Display version information and exit.

       --terse-version=version
              Set terse version output format (Current version 3, or older
              version 2).

       --help Display usage information and exit.

       --cpuclock-test
              Perform test and validation of internal CPU clock

       --crctest[=test]
              Test the speed of the builtin checksumming functions. If no
              argument is given, all of them are tested. Or a comma separated
              list can be passed, in which case the given ones are tested.

       --cmdhelp=command
              Print help information for command.  May be `all' for all
              commands.

       --enghelp=ioengine[,command]
              List all commands defined by ioengine, or print help for command
              defined by ioengine.

       --showcmd=jobfile
              Convert jobfile to a set of command-line options.

       --eta=when
              Specifies when real-time ETA estimate should be printed.  when
              may be one of `always', `never' or `auto'.

       --eta-newline=time
              Force an ETA newline for every `time` period passed.

       --status-interval=time
              Report full output status every `time` period passed.

       --readonly
              Turn on safety read-only checks, preventing any attempted write.

       --section=sec
              Only run section sec from job file. This option can be used
              multiple times to add more sections to run.

       --alloc-size=kb
              Set the internal smalloc pool size to kb kilobytes.

       --warnings-fatal
              All fio parser warnings are fatal, causing fio to exit with an
              error.

       --max-jobs=nr
              Set the maximum allowed number of jobs (threads/processes) to
              support.

       --server=args
              Start a backend server, with args specifying what to listen to.
              See client/server section.

       --daemonize=pidfile
              Background a fio server, writing the pid to the given pid file.

       --client=host
              Instead of running the jobs locally, send and run them on the
              given host.

       --idle-prof=option
              Report cpu idleness on a system or percpu basis
              (option=system,percpu) or run unit work calibration only
              (option=calibrate).

JOB FILE FORMAT
       Job files are in `ini' format. They consist of one or more job
       definitions, which begin with a job name in square brackets and extend
       to the next job name.  The job name can be any ASCII string except
       `global', which has a special meaning.  Following the job name is a
       sequence of zero or more parameters, one per line, that define the
       behavior of the job.  Any line starting with a `;' or `#' character is
       considered a comment and ignored.

       If jobfile is specified as `-', the job file will be read from standard
       input.

   Global Section
       The global section contains default parameters for jobs specified in
       the job file.  A job is only affected by global sections residing above
       it, and there may be any number of global sections.  Specific job
       definitions may override any parameter set in global sections.

JOB PARAMETERS
   Types
       Some parameters may take arguments of a specific type.  The types used
       are:

       str    String: a sequence of alphanumeric characters.

       int    SI integer: a whole number, possibly containing a suffix
              denoting the base unit of the value.  Accepted suffixes are `k',
              'M', 'G', 'T', and 'P', denoting kilo (1024), mega (1024^2),
              giga (1024^3), tera (1024^4), and peta (1024^5) respectively. If
              prefixed with '0x', the value is assumed to be base 16
              (hexadecimal). A suffix may include a trailing 'b', for instance
              'kb' is identical to 'k'. You can specify a base 10 value by
              using 'KiB', 'MiB','GiB', etc. This is useful for disk drives
              where values are often given in base 10 values. Specifying
              '30GiB' will get you 30*1000^3 bytes.  When specifying times the
              default suffix meaning changes, still denoting the base unit of
              the value, but accepted suffixes are 'D' (days), 'H' (hours),
              'M' (minutes), 'S' Seconds, 'ms' (or msec) milli seconds, 'us'
              (or 'usec') micro seconds. Time values without a unit specify
              seconds.  The suffixes are not case sensitive.

       bool   Boolean: a true or false value. `0' denotes false, `1' denotes
              true.

       irange Integer range: a range of integers specified in the format
              lower:upper or lower-upper. lower and upper may contain a suffix
              as described above.  If an option allows two sets of ranges,
              they are separated with a `,' or `/' character. For example:
              `8-8k/8M-4G'.

       float_list
              List of floating numbers: A list of floating numbers, separated
              by a ':' character.

   Parameter List
       name=str
              May be used to override the job name.  On the command line, this
              parameter has the special purpose of signalling the start of a
              new job.

       description=str
              Human-readable description of the job. It is printed when the
              job is run, but otherwise has no special purpose.

       directory=str
              Prefix filenames with this directory.  Used to place files in a
              location other than `./'.  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 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 filename for
              considerations regarding escaping certain characters on some
              platforms.

       filename=str
              fio normally makes up a file name based on the job name, thread
              number, and file number. If you want to share files between
              threads in a job or several jobs, specify a filename for each of
              them to override the default.  If the I/O engine is file-based,
              you can specify a number of files by separating the names with a
              `:' character. `-' is a reserved name, meaning stdin or stdout,
              depending on the read/write direction set. On Windows, disk
              devices are accessed as \.PhysicalDrive0 for the first device,
              \.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 "/dev/dsk/foo@3,0:c", then you would use
              filename="/dev/dsk/foo@3,0\:c".

       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 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 testfiles.$filenum is specified, file
              number 4 for any job will be named testfiles.4. The default of
              $jobname.$jobnum.$filenum will be used if no other format
              specifier is given.

       lockfile=str
              Fio defaults to not locking any files before it does IO to them.
              If a file or file descriptor is shared, fio can serialize IO 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. This is the default.

                     exclusive
                            Only one thread or process may do IO 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.

       opendir=str Recursively open any files below directory str.

       readwrite=str, rw=str
              Type of I/O pattern.  Accepted values are:

                     read   Sequential reads.

                     write  Sequential writes.

                     trim   Sequential trim (Linux block devices only).

                     randread
                            Random reads.

                     randwrite
                            Random writes.

                     randtrim
                            Random trim (Linux block devices only).

                     rw, readwrite
                            Mixed sequential reads and writes.

                     randrw Mixed random reads and writes.

              For mixed I/O, the default split is 50/50. For certain types of
              io the result may still be skewed a bit, since the speed may be
              different. It is possible to specify a number of IO'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 postfix is used with a sequential IO pattern,
              then the value specified will be added to the generated offset
              for each IO. For instance, using rw=write:4k will skip 4k for
              every write. It turns sequential IO into sequential IO with
              holes. See the rw_sequencer 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 IO offset being generated. Accepted values are:

                     sequential
                            Generate sequential offset

                     identical
                            Generate the same offset

              sequential is only useful for random IO, where fio would
              normally generate a new random offset for every IO. If you
              append eg 8 to randread, you would get a new random offset for
              every 8 IO's. The result would be a seek for only every 8 IO's,
              instead of for every IO. Use rw=randread:8 to specify that. As
              sequential IO 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.

       kb_base=int
              The base unit for a kilobyte. The defacto base is 2^10, 1024.
              Storage manufacturers like to use 10^3 or 1000 as a base ten
              unit instead, for obvious reasons. Allowed values are 1024 or
              1000, with 1024 being the default.

       unified_rw_reporting=bool
              Fio normally reports statistics on a per data direction basis,
              meaning that read, write, and trim are accounted and reported
              separately. If this option is set fio sums the results and
              reports them as "mixed" instead.

       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.

       allrandrepeat=bool
              Seed all random number generators in a predictable way so
              results are repeatable across runs.  Default: false.

       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 randrepeat
              setting.

       use_os_rand=bool
              Fio can either use the random generator supplied by the OS to
              generate random offsets, or it can use its own internal
              generator (based on Tausworthe).  Default is to use the internal
              generator, which is often of better quality and faster. Default:
              false.

       fallocate=str
              Whether pre-allocation is performed when laying down files.
              Accepted values are:

                     none   Do not pre-allocate space.

                     posix  Pre-allocate via posix_fallocate(3).

                     keep   Pre-allocate via 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'.

       fadvise_hint=bool
              Use posix_fadvise(2) to advise the kernel what I/O patterns are
              likely to be issued. Default: true.

       size=int
              Total size of I/O for this job.  fio will run until this many
              bytes have been transferred, unless limited by other options
              (runtime, for instance).  Unless nrfiles and filesize options
              are given, this amount will be divided between the available
              files for the job. If not set, 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.

       io_limit=int
              Normally fio operates within the region set by size, which means
              that the size option sets both the region and size of IO to be
              performed.  Sometimes that is not what you want. With this
              option, it is possible to define just the amount of IO that fio
              should do. For instance, if size is set to 20G and io_limit is
              set to 5G, fio will perform IO within the first 20G but exit
              when 5G have been done.

       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 IO 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.

       filesize=irange
              Individual file sizes. May be a range, in which case fio will
              select sizes for files at random within the given range, limited
              to size in total (if that is given). If filesize is not
              specified, each created file is the same size.

       file_append=bool
              Perform IO 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 offset to the size of a file. This option is ignored on
              non-regular files.

       blocksize=int[,int], bs=int[,int]
              Block size for I/O units.  Default: 4k.  Values for reads,
              writes, and trims can be specified separately in the format
              read,write,trim either of which may be empty to leave that value
              at its default. If a trailing comma isn't given, the remainder
              will inherit the last value set.

       blocksize_range=irange[,irange], bsrange=irange[,irange]
              Specify a range of I/O block sizes.  The issued I/O unit will
              always be a multiple of the minimum size, unless
              blocksize_unaligned is set.  Applies to both reads and writes if
              only one range is given, but can be specified separately with a
              comma separating the values. Example: bsrange=1k-4k,2k-8k.  Also
              (see blocksize).

       bssplit=str
              This option allows even finer grained control of the block sizes
              issued, not just even splits between them. With this option, you
              can weight various block sizes for exact control of the issued
              IO for a job that has mixed block sizes. The format of the
              option is bssplit=blocksize/percentage, optionally adding as
              many definitions as needed separated by a colon.  Example:
              bssplit=4k/10:64k/50:32k/40 would issue 50% 64k blocks, 10% 4k
              blocks and 40% 32k blocks. bssplit also supports giving separate
              splits to reads and writes. The format is identical to what the
              bs option accepts, the read and write parts are separated with a
              comma.

       blocksize_unaligned, bs_unaligned
              If set, any size in blocksize_range may be used.  This typically
              won't work with direct I/O, as that normally requires sector
              alignment.

       blockalign=int[,int], ba=int[,int]
              At what boundary to align random IO offsets. Defaults to the
              same as 'blocksize' the minimum blocksize given.  Minimum
              alignment is typically 512b for using direct IO, 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.

       bs_is_seq_rand=bool
              If this option is set, fio will use the normal read,write
              blocksize settings as sequential,random instead. Any random read
              or write will use the WRITE blocksize settings, and any
              sequential read or write will use the READ blocksize setting.

       zero_buffers
              Initialize buffers with all zeros. Default: fill buffers with
              random data.  The resulting IO buffers will not be completely
              zeroed, unless scramble_buffers is also turned off.

       refill_buffers
              If this option is given, fio will refill the IO 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.

       scramble_buffers=bool
              If refill_buffers is too costly and the target is using data
              deduplication, then setting this option will slightly modify the
              IO 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.

       buffer_compress_percentage=int
              If this is set, then fio will attempt to provide IO buffer
              content (on WRITEs) that compress to the specified level. Fio
              does this by providing a mix of random data and zeroes. Note
              that this is per block size unit, for file/disk wide compression
              level that matches this setting, you'll also want to set
              refill_buffers.

       buffer_compress_chunk=int
              See 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 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 IO buffer.

       buffer_pattern=str
              If set, fio will fill the IO buffers with this pattern. If not
              set, the contents of IO 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 "".

       nrfiles=int
              Number of files to use for this job.  Default: 1.

       openfiles=int
              Number of files to keep open at the same time.  Default:
              nrfiles.

       file_service_type=str
              Defines how files to service are selected.  The following types
              are defined:

                     random Choose a file at random.

                     roundrobin
                            Round robin over opened files (default).

                     sequential
                            Do each file in the set sequentially.

              The number of I/Os to issue before switching to a new file can
              be specified by appending `:int' to the service type.

       ioengine=str
              Defines how the job issues I/O.  The following types are
              defined:

                     sync   Basic read(2) or write(2) I/O.  fseek(2) is used
                            to position the I/O location.

                     psync  Basic pread(2) or pwrite(2) I/O.

                     vsync  Basic readv(2) or writev(2) I/O. Will emulate
                            queuing by coalescing adjacent IOs into a single
                            submission.

                     pvsync Basic preadv(2) or pwritev(2) I/O.

                     libaio Linux native asynchronous I/O. This ioengine
                            defines engine specific options.

                     posixaio
                            POSIX asynchronous I/O using aio_read(3) and
                            aio_write(3).

                     solarisaio
                            Solaris native asynchronous I/O.

                     windowsaio
                            Windows native asynchronous I/O.

                     mmap   File is memory mapped with mmap(2) and data copied
                            using memcpy(3).

                     splice splice(2) is used to transfer the data and
                            vmsplice(2) to transfer data from user-space to
                            the kernel.

                     syslet-rw
                            Use the syslet system calls to make regular
                            read/write asynchronous.

                     sg     SCSI generic sg v3 I/O. May be either synchronous
                            using the SG_IO ioctl, or if the target is an sg
                            character device, we use read(2) and write(2) for
                            asynchronous I/O.

                     null   Doesn't transfer any data, just pretends to.
                            Mainly used to exercise fio itself and for
                            debugging and testing purposes.

                     net    Transfer over the network.  The protocol to be
                            used can be defined with the protocol parameter.
                            Depending on the protocol, filename, hostname,
                            port, or listen must be specified.  This ioengine
                            defines engine specific options.

                     netsplice
                            Like net, but uses splice(2) and vmsplice(2) to
                            map data and send/receive. This ioengine defines
                            engine specific options.

                     cpuio  Doesn't transfer any data, but burns CPU cycles
                            according to cpuload and cpucycles parameters.

                     guasi  The GUASI I/O engine is the Generic Userspace
                            Asynchronous Syscall Interface approach to
                            asynchronous I/O.
                            See <http://www.xmailserver.org/guasi-lib.html>.

                     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.

                     external
                            Loads an external I/O engine object file.  Append
                            the engine filename as `:enginepath'.

                     falloc
                               IO engine that does regular linux native
                            fallocate call to simulate data transfer as fio
                            ioengine
                              DDIR_READ  does fallocate(,mode =
                            FALLOC_FL_KEEP_SIZE,)
                              DIR_WRITE does fallocate(,mode = 0)
                              DDIR_TRIM does fallocate(,mode =
                            FALLOC_FL_KEEP_SIZE|FALLOC_FL_PUNCH_HOLE)

                     e4defrag
                            IO engine that does regular EXT4_IOC_MOVE_EXT
                            ioctls to simulate defragment activity request to
                            DDIR_WRITE event

                     rbd    IO 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
                            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.

       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 degress when 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 direct=1, since buffered IO is not
              async on that OS. Keep an eye on the IO depth distribution in
              the fio output to verify that the achieved depth is as expected.
              Default: 1.

       iodepth_batch=int
              Number of I/Os to submit at once.  Default: iodepth.

       iodepth_batch_complete=int
              This defines how many pieces of IO to retrieve at once. It
              defaults to 1 which
               means that we'll ask for a minimum of 1 IO in the retrieval
              process from the kernel. The IO retrieval will go on until we
              hit the limit set by iodepth_low. If this variable is set to 0,
              then fio will always check for completed events before queuing
              more IO. This helps reduce IO latency, at the cost of more
              retrieval system calls.

       iodepth_low=int
              Low watermark indicating when to start filling the queue again.
              Default: iodepth.

       direct=bool
              If true, use non-buffered I/O (usually O_DIRECT).  Default:
              false.

       atomic=bool
              If value is true, attempt to use atomic direct IO. Atomic writes
              are guaranteed to be stable once acknowledged by the operating
              system. Only Linux supports O_ATOMIC right now.

       buffered=bool
              If true, use buffered I/O.  This is the opposite of the direct
              parameter.  Default: true.

       offset=int
              Offset in the file to start I/O. Data before the offset will not
              be touched.

       offset_increment=int
              If this is provided, then the real offset becomes the 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 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.

       number_ios=int
              Fio will normally perform IOs until it has exhausted the size of
              the region set by 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 IOs to perform. When fio
              reaches this number, it will exit normally and report status.

       fsync=int
              How many I/Os to perform before issuing an fsync(2) of dirty
              data.  If 0, don't sync.  Default: 0.

       fdatasync=int
              Like fsync, but uses fdatasync(2) instead to only sync the data
              parts of the file. Default: 0.

       write_barrier=int
              Make every Nth write a barrier write.

       sync_file_range=str:int
              Use sync_file_range(2) for every val number of write operations.
              Fio will track range of writes that have happened since the last
              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_WRITE


              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 sync_file_range(2) man page.  This option
              is Linux specific.

       overwrite=bool
              If writing, setup the file first and do overwrites.  Default:
              false.

       end_fsync=bool
              Sync file contents when a write stage has completed.  Default:
              false.

       fsync_on_close=bool
              If true, sync file contents on close.  This differs from
              end_fsync in that it will happen on every close, not just at the
              end of the job.  Default: false.

       rwmixread=int
              Percentage of a mixed workload that should be reads. Default:
              50.

       rwmixwrite=int
              Percentage of a mixed workload that should be writes.  If
              rwmixread and rwmixwrite are given and do not sum to 100%, the
              latter of the two overrides 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.

       random_distribution=str:float
              By default, fio will use a completely uniform random
              distribution when asked to perform random IO. 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


              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,
              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.

       percentage_random=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. It is
              possible to set different values for reads, writes, and trim. To
              do so, simply use a comma separated list. See blocksize.

       norandommap
              Normally fio will cover every block of the file when doing
              random I/O. If this parameter is given, a new offset will be
              chosen without looking at past I/O history.  This parameter is
              mutually exclusive with verify.

       softrandommap=bool
              See 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.

       random_generator=str
              Fio supports the following engines for generating IO offsets for
              random IO:

              tausworthe
                     Strong 2^88 cycle random number generator

              lfsr   Linear feedback shift register 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 IO 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.

       nice=int
              Run job with given nice value.  See nice(2).

       prio=int
              Set I/O priority value of this job between 0 (highest) and 7
              (lowest).  See ionice(1).

       prioclass=int
              Set I/O priority class.  See ionice(1).

       thinktime=int
              Stall job for given number of microseconds between issuing I/Os.

       thinktime_spin=int
              Pretend to spend CPU time for given number of microseconds,
              sleeping the rest of the time specified by thinktime.  Only
              valid if thinktime is set.

       thinktime_blocks=int
              Only valid if thinktime is set - control how many blocks to
              issue, before waiting thinktime microseconds. If not set,
              defaults to 1 which will make fio wait thinktime microseconds
              after every block. This effectively makes any queue depth
              setting redundant, since no more than 1 IO 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.  Default: 1.

       rate=int
              Cap bandwidth used by this job. The number is in bytes/sec, the
              normal postfix rules apply. You can use rate=500k to limit reads
              and writes to 500k each, or you can specify read and writes
              separately. Using rate=1m,500k would limit reads to 1MB/sec and
              writes to 500KB/sec. Capping only reads or writes can be done
              with rate=,500k or rate=500k,. The former will only limit writes
              (to 500KB/sec), the latter will only limit reads.

       ratemin=int
              Tell fio to do whatever it can to maintain at least the given
              bandwidth.  Failing to meet this requirement will cause the job
              to exit. The same format as rate is used for read vs write
              separation.

       rate_iops=int
              Cap the bandwidth to this number of IOPS. Basically the same as
              rate, just specified independently of bandwidth. The same format
              as rate is used for read vs write separation. If blocksize is a
              range, the smallest block size is used as the metric.

       rate_iops_min=int
              If this rate of I/O is not met, the job will exit. The same
              format as rate is used for read vs write separation.

       ratecycle=int
              Average bandwidth for rate and ratemin over this number of
              milliseconds.  Default: 1000ms.

       latency_target=int
              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. The values is given in microseconds. See
              latency_window and latency_percentile.

       latency_window=int
              Used with latency_target to specify the sample window that the
              job is run at varying queue depths to test the performance. The
              value is given in microseconds.

       latency_percentile=float
              The percentage of IOs that must fall within the criteria
              specified by latency_target and latency_window. If not set, this
              defaults to 100.0, meaning that all IOs must be equal or below
              to the value set by latency_target.

       max_latency=int
              If set, fio will exit the job if it exceeds this maximum
              latency. It will exit with an ETIME error.

       cpumask=int
              Set CPU affinity for this job. int is a bitmask of allowed CPUs
              the job may run on.  See sched_setaffinity(2).

       cpus_allowed=str
              Same as cpumask, but allows a comma-delimited list of CPU
              numbers.

       cpus_allowed_policy=str
              Set the policy of how fio distributes the CPUs specified by
              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 assign one cpu per job. If
              not enough CPUs are given for the jobs listed, then fio will
              roundrobin the CPUs in the set.

       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'.

       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 nodelist is
              needed to be specified. For prefer, only one node is allowed.
              For bind and interleave, nodelist allows comma delimited list of
              numbers, A-B ranges, or 'all'.

       startdelay=irange
              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
              ommited.  Can be given as a range which causes each thread to
              choose randomly out of the range.

       runtime=int
              Terminate processing after the specified number of seconds.

       time_based
              If given, run for the specified runtime duration even if the
              files are completely read or written. The same workload will be
              repeated as many times as runtime allows.

       ramp_time=int
              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 runtime is specified.

       invalidate=bool
              Invalidate buffer-cache for the file prior to starting I/O.
              Default: true.

       sync=bool
              Use synchronous I/O for buffered writes.  For the majority of
              I/O engines, this means using O_SYNC.  Default: false.

       iomem=str, mem=str
              Allocation method for I/O unit buffer.  Allowed values are:

                     malloc Allocate memory with malloc(3).

                     shm    Use shared memory buffers allocated through
                            shmget(2).

                     shmhuge
                            Same as shm, but use huge pages as backing.

                     mmap   Use mmap(2) for allocation.  Uses anonymous memory
                            unless a filename is given after the option in the
                            format `:file'.

                     mmaphuge
                            Same as mmap, but use huge files as backing.

              The amount of memory allocated is the maximum allowed blocksize
              for the job multiplied by iodepth.  For shmhuge or mmaphuge to
              work, the system must have free huge pages allocated.  mmaphuge
              also needs to have hugetlbfs mounted, and file must point there.
              At least on Linux, huge pages must be manually allocated. See
              /proc/sys/vm/nr_hugehages and the documentation for that.
              Normally you just need to echo an appropriate number, eg echoing
              8 will ensure that the OS has 8 huge pages ready for use.

       iomem_align=int, mem_align=int
              This indicates the memory alignment of the IO memory buffers.
              Note that the given alignment is applied to the first IO unit
              buffer, if using iodepth the alignment of the following buffers
              are given by the bs used. In other words, if using a bs that is
              a multiple of the page sized in the system, all buffers will be
              aligned to this value. If using a bs that is not page aligned,
              the alignment of subsequent IO memory buffers is the sum of the
              iomem_align and bs used.

       hugepage-size=int
              Defines the size of a huge page.  Must be at least equal to the
              system setting.  Should be a multiple of 1MB. Default: 4MB.

       exitall
              Terminate all jobs when one finishes.  Default: wait for each
              job to finish.

       bwavgtime=int
              Average bandwidth calculations over the given time in
              milliseconds.  Default: 500ms.

       iopsavgtime=int
              Average IOPS calculations over the given time in milliseconds.
              Default: 500ms.

       create_serialize=bool
              If true, serialize file creation for the jobs.  Default: true.

       create_fsync=bool
              fsync(2) data file after creation.  Default: true.

       create_on_open=bool
              If true, the files are not created until they are opened for IO
              by the job.

       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.

       pre_read=bool
              If this is given, files will be pre-read into memory before
              starting the given IO operation. This will also clear the
              invalidate flag, since it is pointless to pre-read and then drop
              the cache. This will only work for IO engines that are seekable,
              since they allow you to read the same data multiple times. Thus
              it will not work on eg network or splice IO.

       unlink=bool
              Unlink job files when done.  Default: false.

       loops=int
              Specifies the number of iterations (runs of the same workload)
              of this job.  Default: 1.

       verify_only=bool
              Do not perform the 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 time_based
              option set.

       do_verify=bool
              Run the verify phase after a write phase.  Only valid if verify
              is set.  Default: true.

       verify=str
              Method of verifying file contents after each iteration of the
              job.  Allowed values are:

                     md5 crc16 crc32 crc32c crc32c-intel crc64 crc7 sha256
                     sha512 sha1 xxhash
                            Store appropriate checksum in the header of each
                            block. crc32c-intel is hardware accelerated SSE4.2
                            driven, falls back to regular crc32c if not
                            supported by the system.

                     meta   Write extra information about each I/O (timestamp,
                            block number, etc.). The block number is verified.
                            See verify_pattern as well.

                     null   Pretend to verify.  Used for testing internals.

              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.

       verifysort=bool
              If true, written verify blocks are sorted if fio deems it to be
              faster to read them back in a sorted manner.  Default: true.

       verifysort_nr=int
              Pre-load and sort verify blocks for a read workload.

       verify_offset=int
              Swap the verification header with data somewhere else in the
              block before writing.  It is swapped back before verifying.

       verify_interval=int
              Write the verification header for this number of bytes, which
              should divide blocksize.  Default: blocksize.

       verify_pattern=str
              If set, fio will fill the io buffers with this pattern. Fio
              defaults to filling with totally random bytes, but sometimes
              it's interesting to fill with a known pattern for io
              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 verify=meta.

       verify_fatal=bool
              If true, exit the job on the first observed verification
              failure.  Default: false.

       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.

       verify_async=int
              Fio will normally verify IO inline from the submitting thread.
              This option takes an integer describing how many async offload
              threads to create for IO verification instead, causing fio to
              offload the duty of verifying IO contents to one or more
              separate threads.  If using this offload option, even sync IO
              engines can benefit from using an iodepth setting higher than 1,
              as it allows them to have IO in flight while verifies are
              running.

       verify_async_cpus=str
              Tell fio to set the given CPU affinity on the async IO
              verification threads.  See cpus_allowed for the format used.

       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 IO 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.

       verify_backlog_batch=int
              Control how many blocks fio will verify if verify_backlog is
              set. If not set, will default to the value of verify_backlog
              (meaning the entire queue is read back and verified).  If
              verify_backlog_batch is less than verify_backlog then not all
              blocks will be verified,  if verify_backlog_batch is larger than
              verify_backlog,  some blocks will be verified more than once.

       trim_percentage=int
              Number of verify blocks to discard/trim.

       trim_verify_zero=bool
              Verify that trim/discarded blocks are returned as zeroes.

       trim_backlog=int
              Trim after this number of blocks are written.

       trim_backlog_batch=int
              Trim this number of IO blocks.

       experimental_verify=bool
              Enable experimental verification.

       stonewall , wait_for_previous
              Wait for preceding jobs in the job file to exit before starting
              this one.  stonewall implies new_group.

       new_group
              Start a new reporting group.  If not given, all jobs in a file
              will be part of the same reporting group, unless separated by a
              stonewall.

       numjobs=int
              Number of clones (processes/threads performing the same
              workload) of this job.  Default: 1.

       group_reporting
              If set, display per-group reports instead of per-job when
              numjobs is specified.

       thread Use threads created with pthread_create(3) instead of processes
              created with fork(2).

       zonesize=int
              Divide file into zones of the specified size in bytes.  See
              zoneskip.

       zonerange=int
              Give size of an IO zone.  See zoneskip.

       zoneskip=int
              Skip the specified number of bytes when zonesize bytes of data
              have been read.

       write_iolog=str
              Write the issued I/O patterns to the specified file.  Specify a
              separate file for each job, otherwise the iologs will be
              interspersed and the file may be corrupt.

       read_iolog=str
              Replay the I/O patterns contained in the specified file
              generated by write_iolog, or may be a blktrace binary file.

       replay_no_stall=int
              While replaying I/O patterns using read_iolog the default
              behavior attempts to respect timing information between I/Os.
              Enabling replay_no_stall causes I/Os to be replayed as fast as
              possible while still respecting ordering.

       replay_redirect=str
              While replaying I/O patterns using read_iolog the default
              behavior is to replay the IOPS onto the major/minor device that
              each IOP was recorded from.  Setting replay_redirect causes all
              IOPS to be replayed onto the single specified device regardless
              of the device it was recorded from.

       write_bw_log=str
              If given, write a bandwidth log of the jobs in this job file.
              Can be used to store data of the bandwidth of the jobs in their
              lifetime. The included fio_generate_plots script uses gnuplot to
              turn these text files into nice graphs. See write_lat_log for
              behaviour of given filename. For this option, the postfix is
              _bw.x.log, where x is the index of the job (1..N, where N is the
              number of jobs)

       write_lat_log=str
              Same as write_bw_log, but writes I/O completion latencies.  If
              no filename is given with this option, the default filename of
              "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.

       write_iops_log=str
              Same as write_bw_log, but writes IOPS. If no filename is given
              with this option, the default filename of "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.

       log_avg_msec=int
              By default, fio will log an entry in the iops, latency, or bw
              log for every IO 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.  Defaults to 0.

       log_offset=bool
              If this is set, the iolog options will include the byte offset
              for the IO entry as well as the other data values.

       log_compression=int
              If this is set, fio will compress the IO 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 IO 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 IO 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.

       log_store_compressed=bool
              If set, and log_compression is also set, fio will store the log
              files in a compressed format. They can be decompressed with fio,
              using the --inflate-log command line parameter. The files will
              be stored with a .fz suffix.

       disable_lat=bool
              Disable measurements of total latency numbers. Useful only for
              cutting back the number of calls to 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 disable_slat and disable_bw as well.

       disable_clat=bool
              Disable measurements of completion latency numbers. See
              disable_lat.

       disable_slat=bool
              Disable measurements of submission latency numbers. See
              disable_lat.

       disable_bw_measurement=bool
              Disable measurements of throughput/bandwidth numbers. See
              disable_lat.

       lockmem=int
              Pin the specified amount of memory with mlock(2).  Can be used
              to simulate a smaller amount of memory. The amount specified is
              per worker.

       exec_prerun=str
              Before running the job, execute the specified command with
              system(3).
              Output is redirected in a file called jobname.prerun.txt

       exec_postrun=str
              Same as exec_prerun, but the command is executed after the job
              completes.
              Output is redirected in a file called jobname.postrun.txt

       ioscheduler=str
              Attempt to switch the device hosting the file to the specified
              I/O scheduler.

       disk_util=bool
              Generate disk utilization statistics if the platform supports
              it. Default: true.

       clocksource=str
              Use the given clocksource as the base of timing. The supported
              options are:

              gettimeofday
                     gettimeofday(2)

              clock_gettime
                     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.

       gtod_reduce=bool
              Enable all of the gettimeofday(2) reducing options
              (disable_clat, disable_slat, disable_bw) plus reduce precision
              of the timeout somewhat to really shrink the gettimeofday(2)
              call count. With this option enabled, we only do about 0.4% of
              the gtod() calls we would have done if all time keeping was
              enabled.

       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 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 IO workloads need only copy that
              segment, instead of entering the kernel with a 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.

       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 an integer.
              Example: ignore_error=EAGAIN,ENOSPC:122 .
              This option will ignore EAGAIN from READ, and ENOSPC and
              122(EDQUOT) from WRITE.

       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

       profile=str
              Select a specific builtin performance test.

       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

       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.

       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

       uid=int
              Instead of running as the invoking user, set the user ID to this
              value before the thread/process does any work.

       gid=int
              Set group ID, see uid.

       unit_base=int
              Base unit for reporting.  Allowed values are:

              0      Use auto-detection (default).

              8      Byte based.

              1      Bit based.

       flow_id=int
              The ID of the flow. If not specified, it defaults to being a
              global flow. See flow.

       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.

       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.

       flow_sleep=int
              The period of time, in microseconds, to wait after the flow
              watermark has been exceeded before retrying operations

       clat_percentiles=bool
              Enable the reporting of percentiles of completion latencies.

       percentile_list=float_list
              Overwrite the default list of percentiles for completion
              latencies. 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. 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.

   Ioengine Parameters List
       Some parameters 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 ioengine.

       (cpu)cpuload=int
              Attempt to use the specified percentage of CPU cycles.

       (cpu)cpuchunks=int
              Split the load into cycles of the given time. In microseconds.

       (cpu)exit_on_io_done=bool
              Detect when IO threads are done, then exit.

       (libaio)userspace_reap
              Normally, with the libaio engine in use, fio will use the
              io_getevents 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 (eg when
              iodepth_batch_complete=0).

       (net,netsplice)hostname=str
              The host name or IP address to use for TCP or UDP based IO.  If
              the job is a TCP listener or UDP reader, the hostname is not
              used and must be omitted unless it is a valid UDP multicast
              address.

       (net,netsplice)port=int
              The TCP or UDP port to bind to or connect to.

       (net,netsplice)interface=str
              The IP address of the network interface used to send or receive
              UDP multicast packets.

       (net,netsplice)ttl=int
              Time-to-live value for outgoing UDP multicast packets. Default:
              1

       (net,netsplice)nodelay=bool
              Set TCP_NODELAY on TCP connections.

       (net,netsplice)protocol=str, proto=str
              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.

       (net,netsplice)listen
              For TCP network connections, tell fio to listen for incoming
              connections rather than initiating an outgoing connection. The
              hostname must be omitted if this option is used.

       (net,pingpong)=bool
              Normally a network writer will just continue writing data, and a
              network reader will just consume packets. 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.

       (e4defrag,donorname)=str
              File will be used as a block donor (swap extents between files)

       (e4defrag,inplace)=int
              Configure donor file block allocation strategy
              0(default): Preallocate donor's file on init

              1:     allocate space immediately inside defragment event, and
                     free right after event

       (rbd)rbdname=str
              Specifies the name of the RBD.

       (rbd)pool=str
              Specifies the name of the Ceph pool containing the RBD.

       (rbd)clientname=str
              Specifies the username (without the 'client.' prefix) used to
              access the Ceph cluster.

OUTPUT
       While running, fio will display the status of the created jobs.  For
       example:

              Threads: 1: [_r] [24.8% done] [ 13509/  8334 kb/s] [eta
              00h:01m:31s]

       The characters in the first set of brackets denote the current status
       of each threads.  The possible values are:

              P      Setup but not started.
              C      Thread created.
              I      Initialized, waiting.
              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 fsync(2).
              V      Running, verifying written data.
              E      Exited, not reaped by main thread.
              -      Exited, thread reaped.

       The second set of brackets shows the estimated completion percentage of
       the current group.  The third set shows the read and write I/O rate,
       respectively. Finally, the estimated run time of the job is displayed.

       When fio completes (or is interrupted by Ctrl-C), it will show data for
       each thread, each group of threads, and each disk, in that order.

       Per-thread statistics first show the threads client number, group-id,
       and error code.  The remaining figures are as follows:

              io     Number of megabytes of I/O performed.

              bw     Average data rate (bandwidth).

              runt   Threads run time.

              slat   Submission latency minimum, maximum, average and standard
                     deviation. This is the time it took to submit the I/O.

              clat   Completion latency minimum, maximum, average and standard
                     deviation.  This is the time between submission and
                     completion.

              bw     Bandwidth minimum, maximum, percentage of aggregate
                     bandwidth received, average and standard deviation.

              cpu    CPU usage statistics. Includes user and system time,
                     number of context switches this thread went through and
                     number of major and minor page faults.

              IO depths
                     Distribution of I/O depths.  Each depth includes
                     everything less than (or equal) to it, but greater than
                     the previous depth.

              IO issued
                     Number of read/write requests issued, and number of short
                     read/write requests.

              IO latencies
                     Distribution of I/O completion latencies.  The numbers
                     follow the same pattern as IO depths.

       The group statistics show:
              io     Number of megabytes I/O performed.
              aggrb  Aggregate bandwidth of threads in the group.
              minb   Minimum average bandwidth a thread saw.
              maxb   Maximum average bandwidth a thread saw.
              mint   Shortest runtime of threads in the group.
              maxt   Longest runtime of threads in the group.

       Finally, disk statistics are printed with reads first:
              ios    Number of I/Os performed by all groups.
              merge  Number of merges in the I/O scheduler.
              ticks  Number of ticks we kept the disk busy.
              io_queue
                     Total time spent in the disk queue.
              util   Disk utilization.

       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.

TERSE OUTPUT
       If the --minimal / --append-terse options are given, the results will
       be printed/appended in a semicolon-delimited format suitable for
       scripted use.  A job description (if provided) follows on a new line.
       Note that the first number in the line is the version number. If the
       output has to be changed for some reason, this number will be
       incremented by 1 to signify that change.  The fields are:

              terse version, fio version, jobname, groupid, error

              Read status:
                     Total I/O (KB), bandwidth (KB/s), IOPS, runtime (ms)

                     Submission latency:
                            min, max, mean, standard deviation
                     Completion latency:
                            min, max, mean, standard deviation
                     Completion latency percentiles (20 fields):
                            Xth percentile=usec
                     Total latency:
                            min, max, mean, standard deviation
                     Bandwidth:
                            min, max, aggregate percentage of total, mean,
                            standard deviation

              Write status:
                     Total I/O (KB), bandwidth (KB/s), IOPS, runtime (ms)

                     Submission latency:
                            min, max, mean, standard deviation
                     Completion latency:
                            min, max, mean, standard deviation
                     Completion latency percentiles (20 fields):
                            Xth percentile=usec
                     Total latency:
                            min, max, mean, standard deviation
                     Bandwidth:
                            min, max, aggregate percentage of total, mean,
                            standard deviation

              CPU usage:
                     user, system, context switches, major page faults, minor
                     page faults

              IO depth distribution:
                     <=1, 2, 4, 8, 16, 32, >=64

              IO latency distribution:
                     Microseconds:
                            <=2, 4, 10, 20, 50, 100, 250, 500, 750, 1000
                     Milliseconds:
                            <=2, 4, 10, 20, 50, 100, 250, 500, 750, 1000,
                            2000, >=2000

              Disk utilization (1 for each disk used):
                     name, read ios, write ios, read merges, write merges,
                     read ticks, write ticks, read in-queue time, write in-
                     queue time, disk utilization percentage

              Error Info (dependent on continue_on_error, default off):
                     total # errors, first error code

              text description (if provided in config - appears on newline)

CLIENT / SERVER
       Normally you would run fio as a stand-alone application on the machine
       where the IO workload should be generated. However, it is also possible
       to run the frontend and backend of fio separately. This makes it
       possible to have a fio server running on the machine(s) where the IO
       workload should be running, while controlling it from another machine.

       To start the server, you would do:

       fio --server=args

       on that machine, 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.

       When a server is running, you can connect to it from a client. The
       client is run with:

       fio --local-args --client=server --remote-args <job file(s)>

       where --local-args are arguments that are local to 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.  You can connect to multiple clients as well, to do that
       you could run:

       fio --client=server2 --client=server2 <job file(s)>

AUTHORS
       fio was written by Jens Axboe <jens.axboe@oracle.com>, now Jens Axboe
       <jaxboe@fusionio.com>.
       This man page was written by Aaron Carroll <aaronc@cse.unsw.edu.au>
       based on documentation by Jens Axboe.

REPORTING BUGS
       Report bugs to the fio mailing list <fio@vger.kernel.org>.  See README.

SEE ALSO
       For further documentation see HOWTO and README.
       Sample jobfiles are available in the examples directory.




User Manual                      October 2013                           fio(1)