These can be used on the command line or in the job file, and will be
automatically substituted with the current system values when the job
-is run.
+is run. Simple math is also supported on these keywords, so you can
+perform actions like:
+
+size=8*$mb_memory
+
+and get that properly expanded to 8 times the size of memory in the
+machine.
5.0 Detailed list of parameters
int SI integer. A whole number value, which may contain a suffix
describing the base of the number. Accepted suffixes are k/m/g/t/p,
meaning kilo, mega, giga, tera, and peta. The suffix is not case
- sensitive. So if you want to specify 4096, you could either write
+ sensitive, and you may also include trailing 'b' (eg 'kb' is the same
+ as 'k'). So if you want to specify 4096, you could either write
out '4096' or just give 4k. The suffixes signify base 2 values, so
- 1024 is 1k and 1024k is 1m and so on. If the option accepts an upper
- and lower range, use a colon ':' or minus '-' to separate such values.
- May also include a prefix to indicate numbers base. If 0x is used,
- the number is assumed to be hexadecimal. See irange.
+ 1024 is 1k and 1024k is 1m and so on, unless the suffix is explicitly
+ set to a base 10 value using 'kib', 'mib', 'gib', etc. If that is the
+ case, then 1000 is used as the multiplier. This can be handy for
+ disks, since manufacturers generally use base 10 values when listing
+ the capacity of a drive. If the option accepts an upper and lower
+ range, use a colon ':' or minus '-' to separate such values. May also
+ include a prefix to indicate numbers base. If 0x is used, the number
+ is assumed to be hexadecimal. See irange.
bool Boolean. Usually parsed as an integer, however only defined for
true and false (1 and 0).
irange Integer range with suffix. Allows value range to be given, such
can specify a number of files by separating the names with a
':' colon. So if you wanted a job to open /dev/sda and /dev/sdb
as the two working files, you would use
- filename=/dev/sda:/dev/sdb. 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". '-' is a reserved name,
- meaning stdin or stdout. Which of the two depends on the read/write
- direction set.
+ filename=/dev/sda:/dev/sdb. On Windows, disk devices are accessed
+ as \\.\PhysicalDrive0 for the first device, \\.\PhysicalDrive1
+ for the second etc. 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".
+ '-' is a reserved name, meaning stdin or stdout. Which of the
+ two depends on the read/write direction set.
opendir=str Tell fio to recursively add any file it can find in this
directory and down the file system tree.
For the mixed io types, the default is to split them 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 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
+ a number of IO's to do before getting a new offset, this is
+ one 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. 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.
+ 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
randrepeat=bool For random IO workloads, seed the generator in a predictable
way so that results are repeatable across repetitions.
+fallocate=bool By default, fio will use fallocate() to advise the system
+ of the size of the file we are going to write. This can be
+ turned off with fallocate=0. May not be available on all
+ supported platforms. If using ZFS on Solaris this must be
+ set to 0 because ZFS doesn't support it.
+
fadvise_hint=bool By default, fio will use fadvise() to advise the kernel
on what IO patterns it is likely to issue. Sometimes you
want to test specific IO patterns without telling the
limited by other options (such as 'runtime', for instance).
Unless specific nrfiles and filesize options are given,
fio will divide this size between the available files
- specified by the job.
+ specified by the job. If not set, fio will use the full
+ size of the given files or devices. If the the files
+ do not exist, size must be given.
filesize=int Individual file sizes. May be a range, in which case fio
will select sizes for files at random within the given range
fill_device=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.
+ 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.
blocksize=int
bs=int The block size used for the io units. Defaults to 4k. Values
solarisaio Solaris native asynchronous io.
+ windowsaio Windows native asynchronous io.
+
mmap File is memory mapped and data copied
to/from using memcpy(3).
iodepth=int This defines how many io units to keep in flight against
the file. The default is 1 for each file defined in this
job, can be overridden with a larger value for higher
- concurrency.
+ concurrency. 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_submit=int
iodepth_batch=int This defines how many pieces of IO to submit at once.
the depth drain down to 4 before starting to fill it again.
direct=bool If value is true, use non-buffered io. This is usually
- O_DIRECT.
+ O_DIRECT. Note that ZFS on Solaris doesn't support direct io.
buffered=bool If value is true, use buffered io. This is the opposite
of the 'direct' option. Defaults to true.
not sync the file. The exception is the sg io engine, which
synchronizes the disk cache anyway.
-fsyncdata=int Like fsync= but uses fdatasync() to only sync data and not
+fdatasync=int Like fsync= but uses fdatasync() to only sync data and not
metadata blocks.
+ In FreeBSD there is no fdatasync(), this falls back to
+ using fsync()
+
+sync_file_range=str:val Use sync_file_range() for every 'val' number of
+ write operations. Fio will track range of writes that
+ have happened since the last sync_file_range() 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 sync_file_range(2) man page.
+ This option is Linux specific.
overwrite=bool If true, writes to a file will always overwrite existing
data. If the file doesn't already exist, it will be
it in the header of each block.
crc32c-intel Use hardware assisted crc32c calcuation
- provided on SSE4.2 enabled processors.
+ 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.
meta Write extra information about each io
(timestamp, block number etc.). The block
- number is verified.
+ number is verified. See also verify_pattern.
null Only pretend to verify. Useful for testing
internals with ioengine=null, not for much
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".
+ be a hex number that starts with either "0x" or "0X". Use
+ with verify=meta.
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.
+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. On 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,
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.
+
+ will verify the previously written blocks before continuing
+ to write new ones.
+
+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.
stonewall Wait for preceeding jobs in the job file to exit, before
starting this one. Can be used to insert serialization
io on zones of a file.
write_iolog=str Write the issued io patterns to the specified file. See
- read_iolog.
+ read_iolog. Specify a separate file for each job, otherwise
+ the iologs will be interspersed and the file may be corrupt.
read_iolog=str Open an iolog with the specified file name and replay the
io patterns it contains. This can be used to store a
to replay a workload captured by blktrace. See blktrace
for how to capture such logging data. For blktrace replay,
the file needs to be turned into a blkparse binary data
- file first (blktrace <device> -d file_for_fio.bin).
+ file first (blkparse <device> -o /dev/null -d file_for_fio.bin).
+
+replay_no_stall=int When replaying I/O with 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.
+
+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. This is sometimes
+ undesireable 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. replay_redirect=/dev/sdc would cause all
+ IO in the blktrace to be replayed onto /dev/sdc. This means
+ multiple devices will be replayed onto a single, 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. Unfortuantely this also breaks
+ the strict time ordering between multiple device accesses.
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
filename. For this option, the postfix is _bw.log.
write_lat_log=str Same as write_bw_log, except that this option stores io
- completion latencies instead. If no filename is given
- with this option, the default filename of "jobname_type.log"
- is used. Even if the filename is given, fio will still
- append the type of log. So if one specifies
+ submission, completion, and total latencies instead. If no
+ filename is given with this option, the default filename of
+ "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 foo_clat.log and foo_slat.log.
- This helps fio_generate_plot fine the logs automatically.
+ The actual log names will be foo_slat.log, foo_slat.log,
+ and foo_lat.log. This helps fio_generate_plot fine the logs
+ automatically.
lockmem=int Pin down the specified amount of memory with mlock(2). Can
potentially be used instead of removing memory or booting
disk_util=bool Generate disk utilization statistics, if the platform
supports it. Defaults to on.
-disable_clat=bool Disable measurements of completion latency numbers. Useful
+disable_lat=bool Disable measurements of total latency numbers. Useful
only for cutting back the number of calls to gettimeofday,
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_clat.
+ disable_slat.
disable_bw=bool Disable measurements of throughput/bandwidth numbers. See
- disable_clat.
+ disable_lat.
gtod_reduce=bool Enable all of the gettimeofday() reducing options
(disable_clat, disable_slat, disable_bw) plus reduce
for doing these time calls will be excluded from other
uses. Fio will manually clear it from the CPU mask of other
jobs.
+
continue_on_error=bool 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
given in the stats is the first error that was hit during the
run.
+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.
6.0 Interpreting the output
---------------------------
of the results, fio can output the results in a semicolon separated format.
The format is one long line of values, such as:
-client1;0;0;1906777;1090804;1790;0;0;0.000000;0.000000;0;0;0.000000;0.000000;929380;1152890;25.510151%;1078276.333333;128948.113404;0;0;0;0;0;0.000000;0.000000;0;0;0.000000;0.000000;0;0;0.000000%;0.000000;0.000000;100.000000%;0.000000%;324;100.0%;0.0%;0.0%;0.0%;0.0%;0.0%;0.0%;100.0%;0.0%;0.0%;0.0%;0.0%;0.0%
-;0.0%;0.0%;0.0%;0.0%;0.0%
+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 --minimal command line option.
+To enable terse output, use the --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:
- jobname, groupid, error
+ version, jobname, groupid, error
READ status:
KB IO, bandwidth (KB/sec), runtime (msec)
Submission latency: min, max, mean, deviation
Completion latency: min, max, mean, deviation
+ Total latency: min, max, mean, deviation
Bw: min, max, aggregate percentage of total, mean, deviation
WRITE status:
KB IO, bandwidth (KB/sec), runtime (msec)
Submission latency: min, max, mean, deviation
Completion latency: min, max, mean, deviation
+ Total latency: min, max, mean, deviation
Bw: min, max, aggregate percentage of total, mean, deviation
CPU usage: user, system, context switches, major faults, minor faults
IO depths: <=1, 2, 4, 8, 16, 32, >=64
- IO latencies: <=2, 4, 10, 20, 50, 100, 250, 500, 750, 1000, >=2000
- Text description
-
+ IO latencies microseconds: <=2, 4, 10, 20, 50, 100, 250, 500, 750, 1000
+ IO latencies milliseconds: <=2, 4, 10, 20, 50, 100, 250, 500, 750, 1000, 2000, >=2000
+ Additional Info (dependant on continue_on_error, default off): total # errors, first error code
+
+ Additional Info (dependant on description being set): Text description
projects / fio.git / blobdiff