5. Detailed list of parameters
6. Normal output
7. Terse output
-
+8. Trace file format
1.0 Overview and history
------------------------
'#', the entire line is discarded as a comment.
So let's look at a really simple job file that defines two processes, each
-randomly reading from a 128MiB file.
+randomly reading from a 128MB file.
; -- start job file --
[global]
Here we have no global section, as we only have one job defined anyway.
We want to use async io here, with a depth of 4 for each file. We also
-increased the buffer size used to 32KiB and define numjobs to 4 to
+increased the buffer size used to 32KB and define numjobs to 4 to
fork 4 identical jobs. The result is 4 processes each randomly writing
-to their own 64MiB file. Instead of using the above job file, you could
+to their own 64MB file. Instead of using the above job file, you could
have given the parameters on the command line. For this case, you would
specify:
$ fio --name=random-writers --ioengine=libaio --iodepth=4 --rw=randwrite --bs=32k --direct=0 --size=64m --numjobs=4
+4.1 Environment variables
+-------------------------
+
fio also supports environment variable expansion in job files. Any
substring of the form "${VARNAME}" as part of an option value (in other
words, on the right of the `='), will be expanded to the value of the
fio ships with a few example job files, you can also look there for
inspiration.
+4.2 Reserved keywords
+---------------------
+
+Additionally, fio has a set of reserved keywords that will be replaced
+internally with the appropriate value. Those keywords are:
+
+$pagesize The architecture page size of the running system
+$mb_memory Megabytes of total memory in the system
+$ncpus Number of online available CPUs
+
+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. 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
-------------------------------
a string. The following types are used:
str String. This is a sequence of alpha characters.
-time Integer with possible time postfix. In seconds unless otherwise
+time Integer with possible time suffix. In seconds unless otherwise
specified, use eg 10m for 10 minutes. Accepts s/m/h for seconds,
minutes, and hours.
-int SI integer. A whole number value, which may contain a postfix
- describing the base of the number. Accepted postfixes are k/m/g,
- meaning kilo, mega, and giga. So if you want to specify 4096,
- you could either write out '4096' or just give 4k. The postfixes
- 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.
+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, 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, 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 postfix. Allows value range to be given, such
+irange Integer range with suffix. Allows value range to be given, such
as 1024-4096. A colon may also be used as the separator, eg
1k:4k. If the option allows two sets of ranges, they can be
specified with a ',' or '/' delimiter: 1k-4k/8k-32k. Also see
int.
+float_list A list of floating numbers, separated by a ':' character.
With the above in mind, here follows the complete list of fio job
parameters.
files between threads in a job or several jobs, specify
a filename for each of them to override the default. If
the ioengine used is 'net', the filename is the host, port,
- and protocol to use in the format of =host/port/protocol.
+ and protocol to use in the format of =host,port,protocol.
See ioengine=net for more. If the ioengine is file based, you
can specify a number of files by separating the names with a
':' colon. So if you wanted a job to open /dev/sda and /dev/sdb
as the two working files, you would use
- filename=/dev/sda:/dev/sdb. '-' 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.
write Sequential writes
randwrite Random writes
randread Random reads
- rw Sequential mixed reads and writes
+ rw,readwrite Sequential mixed reads and writes
randrw Random mixed reads and writes
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. If the
+ suffix 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.
+ 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. Allow values are
+ 1024 or 1000, with 1024 being the default.
randrepeat=bool For random IO workloads, seed the generator in a predictable
way so that results are repeatable across repetitions.
+use_os_rand=bool Fio can either use the random generator supplied by the OS
+ to generator random offsets, or it can use it's own internal
+ generator (based on Tausworthe). Default is to use the
+ internal generator, which is often of better quality and
+ faster.
+
+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()
+ keep Pre-allocate via fallocate() 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 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. 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.
filesize=int Individual file sizes. May be a range, in which case fio
will select sizes for files at random within the given range
and limited to 'size' in total (if that is given). If not
given, each created file is the same size.
-fill_device=bool Sets size to something really large and waits for ENOSPC (no
+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.
+ 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.
blocksize=int
bs=int The block size used for the io units. Defaults to 4k. Values
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.
+
nrfiles=int Number of files to use for this job. Defaults to 1.
openfiles=int Number of files to keep open at the same time. Defaults to
libaio Linux native asynchronous io. Note that Linux
may only support queued behaviour with
non-buffered IO (set direct=1 or buffered=0).
+ This engine defines engine specific options.
posixaio glibc posix asynchronous io.
solarisaio Solaris native asynchronous io.
+ windowsaio Windows native asynchronous io.
+
mmap File is memory mapped and data copied
to/from using memcpy(3).
itself and for debugging/testing purposes.
net Transfer over the network to given host:port.
- 'filename' must be set appropriately to
- filename=host/port/protocol regardless of send
- or receive, if the latter only the port
- argument is used. 'host' may be an IP address
- or hostname, port is the port number to be used,
- and protocol may be 'udp' or 'tcp'. If no
- protocol is given, TCP is used.
+ Depending on the protocol used, the hostname,
+ port, listen and filename options are used to
+ specify what sort of connection to make, while
+ the protocol option determines which protocol
+ will be used.
+ This engine defines engine specific options.
netsplice Like net, but uses splice/vmsplice to
map data and send/receive.
+ This engine defines engine specific options.
cpuio Doesn't transfer any data, but burns CPU
cycles according to the cpuload= and
for more info on GUASI.
+ rdma The RDMA I/O engine supports both RDMA
+ memory semantics (RDMA_WRITE/RDMA_READ) and
+ channel semantics (Send/Recv) for the
+ InfiniBand, RoCE and iWARP protocols.
+
external Prefix to specify loading an external
IO engine object file. Append the engine
filename, eg ioengine=external:/tmp/foo.o
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.
+ On Windows the synchronous ioengines don't support direct io.
buffered=bool If value is true, use buffered io. This is the opposite
of the 'direct' option. Defaults to true.
the given offset will not be touched. This effectively
caps the file size at real_size - offset.
+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 job. This option is useful if there are several jobs
+ which are intended to operate on a file in parallel in disjoint
+ segments, with even spacing between the starting points.
+
fsync=int If writing to a file, issue a sync of the dirty data
for every number of blocks given. For example, if you give
32 as a parameter, fio will sync the file for every 32
not sync the file. The exception is the sg io engine, which
synchronizes the disk cache anyway.
+fdatasync=int Like fsync= but uses fdatasync() to only sync data and not
+ metadata blocks.
+ In FreeBSD and Windows 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
created before the write phase begins. If the file exists
rwmixwrite=int How large a percentage of the mix should be writes. If both
rwmixread and rwmixwrite is given and the values do not add
up to 100%, the latter of the two will be used to override
- the first.
+ 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.
norandommap Normally fio will cover every block of the file when doing
random IO. If this option is given, fio will just get a
blocksizes (via bsrange=) are used, since fio only tracks
complete rewrites of blocks.
-softrandommap 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
+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.
nice=int Run the job with the given nice value. See man nice(2).
after every block.
rate=int Cap the bandwidth used by this job. The number is in bytes/sec,
- the normal postfix rules apply. You can use rate=500k to limit
+ the normal suffix 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
that for shmhuge and mmaphuge to work, the system must have
free huge pages allocated. This can normally be checked
and set by reading/writing /proc/sys/vm/nr_hugepages on a
- Linux system. Fio assumes a huge page is 4MiB in size. So
+ Linux system. Fio assumes a huge page is 4MB in size. So
to calculate the number of huge pages you need for a given
job file, add up the io depth of all jobs (normally one unless
iodepth= is used) and multiply by the maximum bs set. Then
location should point there. So if it's mounted in /huge,
you would use mem=mmaphuge:/huge/somefile.
+iomem_align=int This indiciates 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 at least be equal
- to the system setting, see /proc/meminfo. Defaults to 4MiB.
+ to the system setting, see /proc/meminfo. Defaults to 4MB.
Should probably always be a multiple of megabytes, so using
hugepage-size=Xm is the preferred way to set this to avoid
setting a non-pow-2 bad value.
bwavgtime=int Average the calculated bandwidth over the given time. Value
is specified in milliseconds.
+iopsavgtime=int Average the calculated IOPS over the given time. Value
+ is specified in milliseconds.
+
create_serialize=bool If true, serialize the file creating for the jobs.
This may be handy to avoid interleaving of data
files, which may greatly depend on the filesystem
create_on_open=bool Don't pre-setup the files for IO, just create open()
when it's time to do IO to that file.
+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.
+ 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 the job files when done. Not the default, as repeated
runs of that job would then waste time recreating the file
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.
sha256 Use sha256 as the checksum function.
+ sha1 Use optimized sha1 as the checksum function.
+
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
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.
+ 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 set, fio will sort written verify blocks when it deems
it faster to read them back in a sorted manner. This is
size of header_interval. blocksize should divide this
evenly.
-verify_pattern=int If set, fio will fill the io buffers with this
+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. The verify_pattern cannot be larger than
- a 32-bit quantity.
+ 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 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. 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.
+
+ 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
+stonewall
+wait_for_previous Wait for preceeding jobs in the job file to exit, before
starting this one. Can be used to insert serialization
points in the job file. A stone wall also implies starting
a new reporting group.
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
jobs in their lifetime. The included fio_generate_plots
script uses gnuplot to turn these text files into nice
- graphs. See write_log_log for behaviour of given
- filename. For this option, the postfix is _bw.log.
+ graphs. See write_lat_log for behaviour of given
+ filename. For this option, the suffix 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.
+
+write_bw_log=str If given, write an IOPS log of the jobs in this job
+ file. See write_bw_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.log" is used. 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.
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.
+
+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, and
+ list the numbers in ascending order. For example,
+ --percentile_list=99.5:99.9 will cause fio to report
+ the values of completion latency below which 99.5% and
+ 99.9% of the observed latencies fell, respectively.
gtod_reduce=bool Enable all of the gettimeofday() reducing options
(disable_clat, disable_slat, disable_bw) plus reduce
uses. Fio will manually clear it from the CPU mask of other
jobs.
+continue_on_error=str Normally fio will exit the job on the first observed
+ failure. If this option is set, fio will continue the job when
+ there is a 'non-fatal error' (EIO or EILSEQ) until the runtime
+ is exceeded or the I/O size specified is completed. If this
+ option is used, there are two more stats that are appended,
+ the total error count and the first error. The error field
+ given in the stats is the first error that was hit during the
+ run.
+
+ The allowed values are:
+
+ none Exit on any IO or verify errors.
+
+ read Continue on read errors, exit on all others.
+
+ write Continue on write errors, exit on all others.
+
+ io Continue on any IO error, exit on all others.
+
+ verify Continue on verify errors, exit on all others.
+
+ all Continue on all errors.
+
+ 0 Backward-compatible alias for 'none'.
+
+ 1 Backward-compatible alias for 'all'.
+
+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.
+
+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
+
+In addition, there are some parameters which are only valid when a specific
+ioengine is in use. These are used identically to normal parameters, with the
+caveat that when used on the command line, they must come after the ioengine
+that defines them is selected.
+
+[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).
+
+[netsplice] hostname=str
+[net] 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.
+
+[netsplice] port=int
+[net] port=int The TCP or UDP port to bind to or connect to.
+
+[netsplice] protocol=str
+[netsplice] proto=str
+[net] protocol=str
+[net] proto=str The network protocol to use. Accepted values are:
+
+ tcp Transmission control protocol
+ udp Unreliable datagram protocol
+ 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] 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.
+
6.0 Interpreting the output
---------------------------
F Running, currently waiting for fsync()
V Running, doing verification of written data.
E Thread exited, not reaped by main thread yet.
-_ Thread reaped.
+_ Thread reaped, or
+X Thread reaped, exited with an error.
+K Thread reaped, exited due to signal.
The other values are fairly self explanatory - number of threads
currently running and doing io, rate of io since last check (read speed
listed first, then write speed), and the estimated completion percentage
and time for the running group. It's impossible to estimate runtime of
-the following groups (if any).
+the following groups (if any). Note that the string is displayed in order,
+so it's possible to tell which of the jobs are currently doing what. The
+first character is the first job defined in the job file, and so forth.
When fio is done (or interrupted by ctrl-c), it will show the data for
each thread, group of threads, and disks in that order. For each data
direction, the output looks like:
Client1 (g=0): err= 0:
- write: io= 32MiB, bw= 666KiB/s, runt= 50320msec
+ write: io= 32MB, bw= 666KB/s, iops=89 , runt= 50320msec
slat (msec): min= 0, max= 136, avg= 0.03, stdev= 1.92
clat (msec): min= 0, max= 631, avg=48.50, stdev=86.82
- bw (KiB/s) : min= 0, max= 1196, per=51.00%, avg=664.02, stdev=681.68
+ bw (KB/s) : min= 0, max= 1196, per=51.00%, avg=664.02, stdev=681.68
cpu : usr=1.49%, sys=0.25%, ctx=7969, majf=0, minf=17
IO depths : 1=0.1%, 2=0.3%, 4=0.5%, 8=99.0%, 16=0.0%, 32=0.0%, >32=0.0%
submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
io= Number of megabytes io performed
bw= Average bandwidth rate
+iops= Average IOs performed per second
runt= The runtime of that thread
slat= Submission latency (avg being the average, stdev being the
standard deviation). This is the time it took to submit
latency, since queue/complete is one operation there. This
value can be in milliseconds or microseconds, fio will choose
the most appropriate base and print that. In the example
- above, milliseconds is the best scale.
+ above, milliseconds is the best scale. Note: in --minimal mode
+ latencies are always expressed in microseconds.
clat= Completion latency. Same names as slat, this denotes the
time from submission to completion of the io pieces. For
sync io, clat will usually be equal (or very close) to 0,
will look like this:
Run status group 0 (all jobs):
- READ: io=64MiB, aggrb=22178, minb=11355, maxb=11814, mint=2840msec, maxt=2955msec
- WRITE: io=64MiB, aggrb=1302, minb=666, maxb=669, mint=50093msec, maxt=50320msec
+ READ: io=64MB, aggrb=22178, minb=11355, maxb=11814, mint=2840msec, maxt=2955msec
+ WRITE: io=64MB, aggrb=1302, minb=666, maxb=669, mint=50093msec, maxt=50320msec
For each data direction, it prints:
util= The disk utilization. A value of 100% means we kept the disk
busy constantly, 50% would be a disk idling half of the time.
+It is also possible to get fio to dump the current output while it is
+running, without terminating the job. To do that, send fio the USR1 signal.
+
7.0 Terse 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
+ terse version, fio version, jobname, groupid, error
READ status:
- KiB IO, bandwidth (KiB/sec), runtime (msec)
- Submission latency: min, max, mean, deviation
- Completion latency: min, max, mean, deviation
- Bw: min, max, aggregate percentage of total, mean, deviation
+ Total IO (KB), bandwidth (KB/sec), IOPS, runtime (msec)
+ Submission latency: min, max, mean, deviation (usec)
+ Completion latency: min, max, mean, deviation (usec)
+ Completion latency percentiles: 20 fields (see below)
+ Total latency: min, max, mean, deviation (usec)
+ Bw (KB/s): min, max, aggregate percentage of total, mean, deviation
WRITE status:
- KiB IO, bandwidth (KiB/sec), runtime (msec)
- Submission latency: min, max, mean, deviation
- Completion latency: min, max, mean, deviation
- Bw: min, max, aggregate percentage of total, mean, deviation
+ Total IO (KB), bandwidth (KB/sec), IOPS, runtime (msec)
+ Submission latency: min, max, mean, deviation (usec)
+ Completion latency: min, max, mean, deviation (usec)
+ Completion latency percentiles: 20 fields (see below)
+ Total latency: min, max, mean, deviation (usec)
+ Bw (KB/s): 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
+ Disk utilization: Disk name, Read ios, write ios,
+ Read merges, write merges,
+ Read ticks, write ticks,
+ Time spent in queue, disk utilization percentage
+ Additional Info (dependant on continue_on_error, default off): total # errors, first error code
+
+ Additional Info (dependant on description being set): Text description
+
+Completion latency percentiles can be a grouping of up to 20 sets, so
+for the terse output fio writes all of them. Each field will look like this:
+
+ 1.00%=6112
+
+which is the Xth percentile, and the usec latency associated with it.
+
+For disk utilization, all disks used by fio are shown. So for each disk
+there will be a disk utilization section.
+
+
+8.0 Trace file format
+---------------------
+There are two trace file format that you can encounter. The older (v1) format
+is unsupported since version 1.20-rc3 (March 2008). It will still be described
+below in case that you get an old trace and want to understand it.
+
+In any case the trace is a simple text file with a single action per line.
+
+
+8.1 Trace file format v1
+------------------------
+Each line represents a single io action in the following format:
+
+rw, offset, length
+
+where rw=0/1 for read/write, and the offset and length entries being in bytes.
+
+This format is not supported in Fio versions => 1.20-rc3.
+
+
+8.2 Trace file format v2
+------------------------
+The second version of the trace file format was added in Fio version 1.17.
+It allows to access more then one file per trace and has a bigger set of
+possible file actions.
+
+The first line of the trace file has to be:
+
+fio version 2 iolog
+
+Following this can be lines in two different formats, which are described below.
+
+The file management format:
+
+filename action
+
+The filename is given as an absolute path. The action can be one of these:
+
+add Add the given filename to the trace
+open Open the file with the given filename. The filename has to have
+ been added with the add action before.
+close Close the file with the given filename. The file has to have been
+ opened before.
+
+
+The file io action format:
+
+filename action offset length
+
+The filename is given as an absolute path, and has to have been added and opened
+before it can be used with this format. The offset and length are given in
+bytes. The action can be one of these:
+wait Wait for 'offset' microseconds. Everything below 100 is discarded.
+read Read 'length' bytes beginning from 'offset'
+write Write 'length' bytes beginning from 'offset'
+sync fsync() the file
+datasync fdatasync() the file
+trim trim the given file from the given 'offset' for 'length' bytes
projects / fio.git / blobdiff