1 .TH fio 1 "October 2013" "User Manual"
3 fio \- flexible I/O tester
6 [\fIoptions\fR] [\fIjobfile\fR]...
9 is a tool that will spawn a number of threads or processes doing a
10 particular type of I/O action as specified by the user.
11 The typical use of fio is to write a job file matching the I/O load
12 one wants to simulate.
15 .BI \-\-debug \fR=\fPtype
16 Enable verbose tracing of various fio actions. May be `all' for all types
17 or individual types separated by a comma (eg \-\-debug=io,file). `help' will
18 list all available tracing options.
20 .BI \-\-output \fR=\fPfilename
21 Write output to \fIfilename\fR.
23 .BI \-\-runtime \fR=\fPruntime
24 Limit run time to \fIruntime\fR seconds.
27 Generate per-job latency logs.
30 Generate per-job bandwidth logs.
33 Print statistics in a terse, semicolon-delimited format.
36 Display version information and exit.
38 .BI \-\-terse\-version \fR=\fPversion
39 Set terse version output format (Current version 3, or older version 2).
42 Display usage information and exit.
45 Perform test and validation of internal CPU clock
47 .BI \-\-crctest[\fR=\fPtest]
48 Test the speed of the builtin checksumming functions. If no argument is given,
49 all of them are tested. Or a comma separated list can be passed, in which
50 case the given ones are tested.
52 .BI \-\-cmdhelp \fR=\fPcommand
53 Print help information for \fIcommand\fR. May be `all' for all commands.
55 .BI \-\-enghelp \fR=\fPioengine[,command]
56 List all commands defined by \fIioengine\fR, or print help for \fIcommand\fR defined by \fIioengine\fR.
58 .BI \-\-showcmd \fR=\fPjobfile
59 Convert \fIjobfile\fR to a set of command-line options.
61 .BI \-\-eta \fR=\fPwhen
62 Specifies when real-time ETA estimate should be printed. \fIwhen\fR may
63 be one of `always', `never' or `auto'.
65 .BI \-\-eta\-newline \fR=\fPtime
66 Force an ETA newline for every `time` period passed.
68 .BI \-\-status\-interval \fR=\fPtime
69 Report full output status every `time` period passed.
72 Turn on safety read-only checks, preventing any attempted write.
74 .BI \-\-section \fR=\fPsec
75 Only run section \fIsec\fR from job file. Multiple of these options can be given, adding more sections to run.
77 .BI \-\-alloc\-size \fR=\fPkb
78 Set the internal smalloc pool size to \fIkb\fP kilobytes.
80 .BI \-\-warnings\-fatal
81 All fio parser warnings are fatal, causing fio to exit with an error.
83 .BI \-\-max\-jobs \fR=\fPnr
84 Set the maximum allowed number of jobs (threads/processes) to support.
86 .BI \-\-server \fR=\fPargs
87 Start a backend server, with \fIargs\fP specifying what to listen to. See client/server section.
89 .BI \-\-daemonize \fR=\fPpidfile
90 Background a fio server, writing the pid to the given pid file.
92 .BI \-\-client \fR=\fPhost
93 Instead of running the jobs locally, send and run them on the given host.
95 .BI \-\-idle\-prof \fR=\fPoption
96 Report cpu idleness on a system or percpu basis (\fIoption\fP=system,percpu) or run unit work calibration only (\fIoption\fP=calibrate).
98 Job files are in `ini' format. They consist of one or more
99 job definitions, which begin with a job name in square brackets and
100 extend to the next job name. The job name can be any ASCII string
101 except `global', which has a special meaning. Following the job name is
102 a sequence of zero or more parameters, one per line, that define the
103 behavior of the job. Any line starting with a `;' or `#' character is
104 considered a comment and ignored.
106 If \fIjobfile\fR is specified as `-', the job file will be read from
109 The global section contains default parameters for jobs specified in the
110 job file. A job is only affected by global sections residing above it,
111 and there may be any number of global sections. Specific job definitions
112 may override any parameter set in global sections.
115 Some parameters may take arguments of a specific type. The types used are:
118 String: a sequence of alphanumeric characters.
121 SI integer: a whole number, possibly containing a suffix denoting the base unit
122 of the value. Accepted suffixes are `k', 'M', 'G', 'T', and 'P', denoting
123 kilo (1024), mega (1024^2), giga (1024^3), tera (1024^4), and peta (1024^5)
124 respectively. The suffix is not case sensitive. If prefixed with '0x', the
125 value is assumed to be base 16 (hexadecimal). A suffix may include a trailing 'b',
126 for instance 'kb' is identical to 'k'. You can specify a base 10 value
127 by using 'KiB', 'MiB', 'GiB', etc. This is useful for disk drives where
128 values are often given in base 10 values. Specifying '30GiB' will get you
132 Boolean: a true or false value. `0' denotes false, `1' denotes true.
135 Integer range: a range of integers specified in the format
136 \fIlower\fR:\fIupper\fR or \fIlower\fR\-\fIupper\fR. \fIlower\fR and
137 \fIupper\fR may contain a suffix as described above. If an option allows two
138 sets of ranges, they are separated with a `,' or `/' character. For example:
142 List of floating numbers: A list of floating numbers, separated by
147 May be used to override the job name. On the command line, this parameter
148 has the special purpose of signalling the start of a new job.
150 .BI description \fR=\fPstr
151 Human-readable description of the job. It is printed when the job is run, but
152 otherwise has no special purpose.
154 .BI directory \fR=\fPstr
155 Prefix filenames with this directory. Used to place files in a location other
158 .BI filename \fR=\fPstr
160 normally makes up a file name based on the job name, thread number, and file
161 number. If you want to share files between threads in a job or several jobs,
162 specify a \fIfilename\fR for each of them to override the default.
163 If the I/O engine is file-based, you can specify
164 a number of files by separating the names with a `:' character. `\-' is a
165 reserved name, meaning stdin or stdout, depending on the read/write direction
168 .BI filename_format \fR=\fPstr
169 If sharing multiple files between jobs, it is usually necessary to have
170 fio generate the exact names that you want. By default, fio will name a file
171 based on the default file format specification of
172 \fBjobname.jobnumber.filenumber\fP. With this option, that can be
173 customized. Fio will recognize and replace the following keywords in this
179 The name of the worker thread or process.
182 The incremental number of the worker thread or process.
185 The incremental number of the file for that worker thread or process.
188 To have dependent jobs share a set of files, this option can be set to
189 have fio generate filenames that are shared between the two. For instance,
190 if \fBtestfiles.$filenum\fR is specified, file number 4 for any job will
191 be named \fBtestfiles.4\fR. The default of \fB$jobname.$jobnum.$filenum\fR
192 will be used if no other format specifier is given.
196 .BI lockfile \fR=\fPstr
197 Fio defaults to not locking any files before it does IO to them. If a file or
198 file descriptor is shared, fio can serialize IO to that file to make the end
199 result consistent. This is usual for emulating real workloads that share files.
205 No locking. This is the default.
208 Only one thread or process may do IO at the time, excluding all others.
211 Read-write locking on the file. Many readers may access the file at the same
212 time, but writes get exclusive access.
216 .BI opendir \fR=\fPstr
217 Recursively open any files below directory \fIstr\fR.
219 .BI readwrite \fR=\fPstr "\fR,\fP rw" \fR=\fPstr
220 Type of I/O pattern. Accepted values are:
231 Sequential trim (Linux block devices only).
240 Random trim (Linux block devices only).
243 Mixed sequential reads and writes.
246 Mixed random reads and writes.
249 For mixed I/O, the default split is 50/50. For certain types of io the result
250 may still be skewed a bit, since the speed may be different. It is possible to
251 specify a number of IO's to do before getting a new offset, this is done by
252 appending a `:\fI<nr>\fR to the end of the string given. For a random read, it
253 would look like \fBrw=randread:8\fR for passing in an offset modifier with a
254 value of 8. If the postfix is used with a sequential IO pattern, then the value
255 specified will be added to the generated offset for each IO. For instance,
256 using \fBrw=write:4k\fR will skip 4k for every write. It turns sequential IO
257 into sequential IO with holes. See the \fBrw_sequencer\fR option.
260 .BI rw_sequencer \fR=\fPstr
261 If an offset modifier is given by appending a number to the \fBrw=<str>\fR line,
262 then this option controls how that number modifies the IO offset being
263 generated. Accepted values are:
268 Generate sequential offset
271 Generate the same offset
274 \fBsequential\fR is only useful for random IO, where fio would normally
275 generate a new random offset for every IO. If you append eg 8 to randread, you
276 would get a new random offset for every 8 IO's. The result would be a seek for
277 only every 8 IO's, instead of for every IO. Use \fBrw=randread:8\fR to specify
278 that. As sequential IO is already sequential, setting \fBsequential\fR for that
279 would not result in any differences. \fBidentical\fR behaves in a similar
280 fashion, except it sends the same offset 8 number of times before generating a
285 .BI kb_base \fR=\fPint
286 The base unit for a kilobyte. The defacto base is 2^10, 1024. Storage
287 manufacturers like to use 10^3 or 1000 as a base ten unit instead, for obvious
288 reasons. Allowed values are 1024 or 1000, with 1024 being the default.
290 .BI unified_rw_reporting \fR=\fPbool
291 Fio normally reports statistics on a per data direction basis, meaning that
292 read, write, and trim are accounted and reported separately. If this option is
293 set, the fio will sum the results and report them as "mixed" instead.
295 .BI randrepeat \fR=\fPbool
296 Seed the random number generator in a predictable way so results are repeatable
297 across runs. Default: true.
299 .BI randseed \fR=\fPint
300 Seed the random number generators based on this seed value, to be able to
301 control what sequence of output is being generated. If not set, the random
302 sequence depends on the \fBrandrepeat\fR setting.
304 .BI use_os_rand \fR=\fPbool
305 Fio can either use the random generator supplied by the OS to generator random
306 offsets, or it can use it's own internal generator (based on Tausworthe).
307 Default is to use the internal generator, which is often of better quality and
308 faster. Default: false.
310 .BI fallocate \fR=\fPstr
311 Whether pre-allocation is performed when laying down files. Accepted values
317 Do not pre-allocate space.
320 Pre-allocate via \fBposix_fallocate\fR\|(3).
323 Pre-allocate via \fBfallocate\fR\|(2) with FALLOC_FL_KEEP_SIZE set.
326 Backward-compatible alias for 'none'.
329 Backward-compatible alias for 'posix'.
332 May not be available on all supported platforms. 'keep' is only
333 available on Linux. If using ZFS on Solaris this must be set to 'none'
334 because ZFS doesn't support it. Default: 'posix'.
337 .BI fadvise_hint \fR=\fPbool
338 Use of \fBposix_fadvise\fR\|(2) to advise the kernel what I/O patterns
339 are likely to be issued. Default: true.
342 Total size of I/O for this job. \fBfio\fR will run until this many bytes have
343 been transferred, unless limited by other options (\fBruntime\fR, for instance).
344 Unless \fBnrfiles\fR and \fBfilesize\fR options are given, this amount will be
345 divided between the available files for the job. If not set, fio will use the
346 full size of the given files or devices. If the files do not exist, size
347 must be given. It is also possible to give size as a percentage between 1 and
348 100. If size=20% is given, fio will use 20% of the full size of the given files
351 .BI fill_device \fR=\fPbool "\fR,\fB fill_fs" \fR=\fPbool
352 Sets size to something really large and waits for ENOSPC (no space left on
353 device) as the terminating condition. Only makes sense with sequential write.
354 For a read workload, the mount point will be filled first then IO started on
355 the result. This option doesn't make sense if operating on a raw device node,
356 since the size of that is already known by the file system. Additionally,
357 writing beyond end-of-device will not return ENOSPC there.
359 .BI filesize \fR=\fPirange
360 Individual file sizes. May be a range, in which case \fBfio\fR will select sizes
361 for files at random within the given range, limited to \fBsize\fR in total (if
362 that is given). If \fBfilesize\fR is not specified, each created file is the
365 .BI blocksize \fR=\fPint[,int] "\fR,\fB bs" \fR=\fPint[,int]
366 Block size for I/O units. Default: 4k. Values for reads, writes, and trims
367 can be specified separately in the format \fIread\fR,\fIwrite\fR,\fItrim\fR
368 either of which may be empty to leave that value at its default. If a trailing
369 comma isn't given, the remainder will inherit the last value set.
371 .BI blocksize_range \fR=\fPirange[,irange] "\fR,\fB bsrange" \fR=\fPirange[,irange]
372 Specify a range of I/O block sizes. The issued I/O unit will always be a
373 multiple of the minimum size, unless \fBblocksize_unaligned\fR is set. Applies
374 to both reads and writes if only one range is given, but can be specified
375 separately with a comma separating the values. Example: bsrange=1k-4k,2k-8k.
376 Also (see \fBblocksize\fR).
378 .BI bssplit \fR=\fPstr
379 This option allows even finer grained control of the block sizes issued,
380 not just even splits between them. With this option, you can weight various
381 block sizes for exact control of the issued IO for a job that has mixed
382 block sizes. The format of the option is bssplit=blocksize/percentage,
383 optionally adding as many definitions as needed separated by a colon.
384 Example: bssplit=4k/10:64k/50:32k/40 would issue 50% 64k blocks, 10% 4k
385 blocks and 40% 32k blocks. \fBbssplit\fR also supports giving separate
386 splits to reads and writes. The format is identical to what the
387 \fBbs\fR option accepts, the read and write parts are separated with a
390 .B blocksize_unaligned\fR,\fP bs_unaligned
391 If set, any size in \fBblocksize_range\fR may be used. This typically won't
392 work with direct I/O, as that normally requires sector alignment.
394 .BI blockalign \fR=\fPint[,int] "\fR,\fB ba" \fR=\fPint[,int]
395 At what boundary to align random IO offsets. Defaults to the same as 'blocksize'
396 the minimum blocksize given. Minimum alignment is typically 512b
397 for using direct IO, though it usually depends on the hardware block size.
398 This option is mutually exclusive with using a random map for files, so it
399 will turn off that option.
401 .BI bs_is_seq_rand \fR=\fPbool
402 If this option is set, fio will use the normal read,write blocksize settings as
403 sequential,random instead. Any random read or write will use the WRITE
404 blocksize settings, and any sequential read or write will use the READ
408 Initialise buffers with all zeros. Default: fill buffers with random data.
411 If this option is given, fio will refill the IO buffers on every submit. The
412 default is to only fill it at init time and reuse that data. Only makes sense
413 if zero_buffers isn't specified, naturally. If data verification is enabled,
414 refill_buffers is also automatically enabled.
416 .BI scramble_buffers \fR=\fPbool
417 If \fBrefill_buffers\fR is too costly and the target is using data
418 deduplication, then setting this option will slightly modify the IO buffer
419 contents to defeat normal de-dupe attempts. This is not enough to defeat
420 more clever block compression attempts, but it will stop naive dedupe
421 of blocks. Default: true.
423 .BI buffer_compress_percentage \fR=\fPint
424 If this is set, then fio will attempt to provide IO buffer content (on WRITEs)
425 that compress to the specified level. Fio does this by providing a mix of
426 random data and zeroes. Note that this is per block size unit, for file/disk
427 wide compression level that matches this setting, you'll also want to set
428 \fBrefill_buffers\fR.
430 .BI buffer_compress_chunk \fR=\fPint
431 See \fBbuffer_compress_percentage\fR. This setting allows fio to manage how
432 big the ranges of random data and zeroed data is. Without this set, fio will
433 provide \fBbuffer_compress_percentage\fR of blocksize random data, followed by
434 the remaining zeroed. With this set to some chunk size smaller than the block
435 size, fio can alternate random and zeroed data throughout the IO buffer.
437 .BI buffer_pattern \fR=\fPstr
438 If set, fio will fill the io buffers with this pattern. If not set, the contents
439 of io buffers is defined by the other options related to buffer contents. The
440 setting can be any pattern of bytes, and can be prefixed with 0x for hex
443 .BI nrfiles \fR=\fPint
444 Number of files to use for this job. Default: 1.
446 .BI openfiles \fR=\fPint
447 Number of files to keep open at the same time. Default: \fBnrfiles\fR.
449 .BI file_service_type \fR=\fPstr
450 Defines how files to service are selected. The following types are defined:
455 Choose a file at random.
458 Round robin over open files (default).
461 Do each file in the set sequentially.
464 The number of I/Os to issue before switching a new file can be specified by
465 appending `:\fIint\fR' to the service type.
468 .BI ioengine \fR=\fPstr
469 Defines how the job issues I/O. The following types are defined:
474 Basic \fBread\fR\|(2) or \fBwrite\fR\|(2) I/O. \fBfseek\fR\|(2) is used to
475 position the I/O location.
478 Basic \fBpread\fR\|(2) or \fBpwrite\fR\|(2) I/O.
481 Basic \fBreadv\fR\|(2) or \fBwritev\fR\|(2) I/O. Will emulate queuing by
482 coalescing adjacent IOs into a single submission.
485 Basic \fBpreadv\fR\|(2) or \fBpwritev\fR\|(2) I/O.
488 Linux native asynchronous I/O. This ioengine defines engine specific options.
491 POSIX asynchronous I/O using \fBaio_read\fR\|(3) and \fBaio_write\fR\|(3).
494 Solaris native asynchronous I/O.
497 Windows native asynchronous I/O.
500 File is memory mapped with \fBmmap\fR\|(2) and data copied using
504 \fBsplice\fR\|(2) is used to transfer the data and \fBvmsplice\fR\|(2) to
505 transfer data from user-space to the kernel.
508 Use the syslet system calls to make regular read/write asynchronous.
511 SCSI generic sg v3 I/O. May be either synchronous using the SG_IO ioctl, or if
512 the target is an sg character device, we use \fBread\fR\|(2) and
513 \fBwrite\fR\|(2) for asynchronous I/O.
516 Doesn't transfer any data, just pretends to. Mainly used to exercise \fBfio\fR
517 itself and for debugging and testing purposes.
520 Transfer over the network. The protocol to be used can be defined with the
521 \fBprotocol\fR parameter. Depending on the protocol, \fBfilename\fR,
522 \fBhostname\fR, \fBport\fR, or \fBlisten\fR must be specified.
523 This ioengine defines engine specific options.
526 Like \fBnet\fR, but uses \fBsplice\fR\|(2) and \fBvmsplice\fR\|(2) to map data
527 and send/receive. This ioengine defines engine specific options.
530 Doesn't transfer any data, but burns CPU cycles according to \fBcpuload\fR and
531 \fBcpucycles\fR parameters.
534 The GUASI I/O engine is the Generic Userspace Asynchronous Syscall Interface
535 approach to asynchronous I/O.
537 See <http://www.xmailserver.org/guasi\-lib.html>.
540 The RDMA I/O engine supports both RDMA memory semantics (RDMA_WRITE/RDMA_READ)
541 and channel semantics (Send/Recv) for the InfiniBand, RoCE and iWARP protocols.
544 Loads an external I/O engine object file. Append the engine filename as
548 IO engine that does regular linux native fallocate call to simulate data
549 transfer as fio ioengine
551 DDIR_READ does fallocate(,mode = FALLOC_FL_KEEP_SIZE,)
553 DIR_WRITE does fallocate(,mode = 0)
555 DDIR_TRIM does fallocate(,mode = FALLOC_FL_KEEP_SIZE|FALLOC_FL_PUNCH_HOLE)
558 IO engine that does regular EXT4_IOC_MOVE_EXT ioctls to simulate defragment activity
559 request to DDIR_WRITE event
564 .BI iodepth \fR=\fPint
565 Number of I/O units to keep in flight against the file. Note that increasing
566 iodepth beyond 1 will not affect synchronous ioengines (except for small
567 degress when verify_async is in use). Even async engines my impose OS
568 restrictions causing the desired depth not to be achieved. This may happen on
569 Linux when using libaio and not setting \fBdirect\fR=1, since buffered IO is
570 not async on that OS. Keep an eye on the IO depth distribution in the
571 fio output to verify that the achieved depth is as expected. Default: 1.
573 .BI iodepth_batch \fR=\fPint
574 Number of I/Os to submit at once. Default: \fBiodepth\fR.
576 .BI iodepth_batch_complete \fR=\fPint
577 This defines how many pieces of IO to retrieve at once. It defaults to 1 which
578 means that we'll ask for a minimum of 1 IO in the retrieval process from the
579 kernel. The IO retrieval will go on until we hit the limit set by
580 \fBiodepth_low\fR. If this variable is set to 0, then fio will always check for
581 completed events before queuing more IO. This helps reduce IO latency, at the
582 cost of more retrieval system calls.
584 .BI iodepth_low \fR=\fPint
585 Low watermark indicating when to start filling the queue again. Default:
588 .BI direct \fR=\fPbool
589 If true, use non-buffered I/O (usually O_DIRECT). Default: false.
591 .BI atomic \fR=\fPbool
592 If value is true, attempt to use atomic direct IO. Atomic writes are guaranteed
593 to be stable once acknowledged by the operating system. Only Linux supports
596 .BI buffered \fR=\fPbool
597 If true, use buffered I/O. This is the opposite of the \fBdirect\fR parameter.
600 .BI offset \fR=\fPint
601 Offset in the file to start I/O. Data before the offset will not be touched.
603 .BI offset_increment \fR=\fPint
604 If this is provided, then the real offset becomes the
605 offset + offset_increment * thread_number, where the thread number is a counter
606 that starts at 0 and is incremented for each job. This option is useful if
607 there are several jobs which are intended to operate on a file in parallel in
608 disjoint segments, with even spacing between the starting points.
610 .BI number_ios \fR=\fPint
611 Fio will normally perform IOs until it has exhausted the size of the region
612 set by \fBsize\fR, or if it exhaust the allocated time (or hits an error
613 condition). With this setting, the range/size can be set independently of
614 the number of IOs to perform. When fio reaches this number, it will exit
615 normally and report status.
618 How many I/Os to perform before issuing an \fBfsync\fR\|(2) of dirty data. If
619 0, don't sync. Default: 0.
621 .BI fdatasync \fR=\fPint
622 Like \fBfsync\fR, but uses \fBfdatasync\fR\|(2) instead to only sync the
623 data parts of the file. Default: 0.
625 .BI write_barrier \fR=\fPint
626 Make every Nth write a barrier write.
628 .BI sync_file_range \fR=\fPstr:int
629 Use \fBsync_file_range\fR\|(2) for every \fRval\fP number of write operations. Fio will
630 track range of writes that have happened since the last \fBsync_file_range\fR\|(2) call.
631 \fRstr\fP can currently be one or more of:
635 SYNC_FILE_RANGE_WAIT_BEFORE
638 SYNC_FILE_RANGE_WRITE
641 SYNC_FILE_RANGE_WRITE
645 So if you do sync_file_range=wait_before,write:8, fio would use
646 \fBSYNC_FILE_RANGE_WAIT_BEFORE | SYNC_FILE_RANGE_WRITE\fP for every 8 writes.
647 Also see the \fBsync_file_range\fR\|(2) man page. This option is Linux specific.
649 .BI overwrite \fR=\fPbool
650 If writing, setup the file first and do overwrites. Default: false.
652 .BI end_fsync \fR=\fPbool
653 Sync file contents when a write stage has completed. Default: false.
655 .BI fsync_on_close \fR=\fPbool
656 If true, sync file contents on close. This differs from \fBend_fsync\fR in that
657 it will happen on every close, not just at the end of the job. Default: false.
659 .BI rwmixread \fR=\fPint
660 Percentage of a mixed workload that should be reads. Default: 50.
662 .BI rwmixwrite \fR=\fPint
663 Percentage of a mixed workload that should be writes. If \fBrwmixread\fR and
664 \fBrwmixwrite\fR are given and do not sum to 100%, the latter of the two
665 overrides the first. This may interfere with a given rate setting, if fio is
666 asked to limit reads or writes to a certain rate. If that is the case, then
667 the distribution may be skewed. Default: 50.
669 .BI random_distribution \fR=\fPstr:float
670 By default, fio will use a completely uniform random distribution when asked
671 to perform random IO. Sometimes it is useful to skew the distribution in
672 specific ways, ensuring that some parts of the data is more hot than others.
673 Fio includes the following distribution models:
677 Uniform random distribution
687 When using a zipf or pareto distribution, an input value is also needed to
688 define the access pattern. For zipf, this is the zipf theta. For pareto,
689 it's the pareto power. Fio includes a test program, genzipf, that can be
690 used visualize what the given input values will yield in terms of hit rates.
691 If you wanted to use zipf with a theta of 1.2, you would use
692 random_distribution=zipf:1.2 as the option. If a non-uniform model is used,
693 fio will disable use of the random map.
695 .BI percentage_random \fR=\fPint
696 For a random workload, set how big a percentage should be random. This defaults
697 to 100%, in which case the workload is fully random. It can be set from
698 anywhere from 0 to 100. Setting it to 0 would make the workload fully
699 sequential. It is possible to set different values for reads, writes, and
700 trim. To do so, simply use a comma separated list. See \fBblocksize\fR.
703 Normally \fBfio\fR will cover every block of the file when doing random I/O. If
704 this parameter is given, a new offset will be chosen without looking at past
705 I/O history. This parameter is mutually exclusive with \fBverify\fR.
707 .BI softrandommap \fR=\fPbool
708 See \fBnorandommap\fR. If fio runs with the random block map enabled and it
709 fails to allocate the map, if this option is set it will continue without a
710 random block map. As coverage will not be as complete as with random maps, this
711 option is disabled by default.
713 .BI random_generator \fR=\fPstr
714 Fio supports the following engines for generating IO offsets for random IO:
718 Strong 2^88 cycle random number generator
721 Linear feedback shift register generator
725 Tausworthe is a strong random number generator, but it requires tracking on the
726 side if we want to ensure that blocks are only read or written once. LFSR
727 guarantees that we never generate the same offset twice, and it's also less
728 computationally expensive. It's not a true random generator, however, though
729 for IO purposes it's typically good enough. LFSR only works with single block
730 sizes, not with workloads that use multiple block sizes. If used with such a
731 workload, fio may read or write some blocks multiple times.
734 Run job with given nice value. See \fBnice\fR\|(2).
737 Set I/O priority value of this job between 0 (highest) and 7 (lowest). See
740 .BI prioclass \fR=\fPint
741 Set I/O priority class. See \fBionice\fR\|(1).
743 .BI thinktime \fR=\fPint
744 Stall job for given number of microseconds between issuing I/Os.
746 .BI thinktime_spin \fR=\fPint
747 Pretend to spend CPU time for given number of microseconds, sleeping the rest
748 of the time specified by \fBthinktime\fR. Only valid if \fBthinktime\fR is set.
750 .BI thinktime_blocks \fR=\fPint
751 Only valid if thinktime is set - control how many blocks to issue, before
752 waiting \fBthinktime\fR microseconds. If not set, defaults to 1 which will
753 make fio wait \fBthinktime\fR microseconds after every block. This
754 effectively makes any queue depth setting redundant, since no more than 1 IO
755 will be queued before we have to complete it and do our thinktime. In other
756 words, this setting effectively caps the queue depth if the latter is larger.
760 Cap bandwidth used by this job. The number is in bytes/sec, the normal postfix
761 rules apply. You can use \fBrate\fR=500k to limit reads and writes to 500k each,
762 or you can specify read and writes separately. Using \fBrate\fR=1m,500k would
763 limit reads to 1MB/sec and writes to 500KB/sec. Capping only reads or writes
764 can be done with \fBrate\fR=,500k or \fBrate\fR=500k,. The former will only
765 limit writes (to 500KB/sec), the latter will only limit reads.
767 .BI ratemin \fR=\fPint
768 Tell \fBfio\fR to do whatever it can to maintain at least the given bandwidth.
769 Failing to meet this requirement will cause the job to exit. The same format
770 as \fBrate\fR is used for read vs write separation.
772 .BI rate_iops \fR=\fPint
773 Cap the bandwidth to this number of IOPS. Basically the same as rate, just
774 specified independently of bandwidth. The same format as \fBrate\fR is used for
775 read vs write separation. If \fBblocksize\fR is a range, the smallest block
776 size is used as the metric.
778 .BI rate_iops_min \fR=\fPint
779 If this rate of I/O is not met, the job will exit. The same format as \fBrate\fR
780 is used for read vs write separation.
782 .BI ratecycle \fR=\fPint
783 Average bandwidth for \fBrate\fR and \fBratemin\fR over this number of
784 milliseconds. Default: 1000ms.
786 .BI latency_target \fR=\fPint
787 If set, fio will attempt to find the max performance point that the given
788 workload will run at while maintaining a latency below this target. The
789 values is given in microseconds. See \fBlatency_window\fR and
790 \fBlatency_percentile\fR.
792 .BI latency_window \fR=\fPint
793 Used with \fBlatency_target\fR to specify the sample window that the job
794 is run at varying queue depths to test the performance. The value is given
797 .BI latency_percentile \fR=\fPfloat
798 The percentage of IOs that must fall within the criteria specified by
799 \fBlatency_target\fR and \fBlatency_window\fR. If not set, this defaults
800 to 100.0, meaning that all IOs must be equal or below to the value set
801 by \fBlatency_target\fR.
803 .BI max_latency \fR=\fPint
804 If set, fio will exit the job if it exceeds this maximum latency. It will exit
807 .BI cpumask \fR=\fPint
808 Set CPU affinity for this job. \fIint\fR is a bitmask of allowed CPUs the job
809 may run on. See \fBsched_setaffinity\fR\|(2).
811 .BI cpus_allowed \fR=\fPstr
812 Same as \fBcpumask\fR, but allows a comma-delimited list of CPU numbers.
814 .BI numa_cpu_nodes \fR=\fPstr
815 Set this job running on specified NUMA nodes' CPUs. The arguments allow
816 comma delimited list of cpu numbers, A-B ranges, or 'all'.
818 .BI numa_mem_policy \fR=\fPstr
819 Set this job's memory policy and corresponding NUMA nodes. Format of
823 .B <mode>[:<nodelist>]
826 is one of the following memory policy:
828 .B default, prefer, bind, interleave, local
831 For \fBdefault\fR and \fBlocal\fR memory policy, no \fBnodelist\fR is
832 needed to be specified. For \fBprefer\fR, only one node is
833 allowed. For \fBbind\fR and \fBinterleave\fR, \fBnodelist\fR allows
834 comma delimited list of numbers, A-B ranges, or 'all'.
836 .BI startdelay \fR=\fPint
837 Delay start of job for the specified number of seconds.
839 .BI runtime \fR=\fPint
840 Terminate processing after the specified number of seconds.
843 If given, run for the specified \fBruntime\fR duration even if the files are
844 completely read or written. The same workload will be repeated as many times
845 as \fBruntime\fR allows.
847 .BI ramp_time \fR=\fPint
848 If set, fio will run the specified workload for this amount of time before
849 logging any performance numbers. Useful for letting performance settle before
850 logging results, thus minimizing the runtime required for stable results. Note
851 that the \fBramp_time\fR is considered lead in time for a job, thus it will
852 increase the total runtime if a special timeout or runtime is specified.
854 .BI invalidate \fR=\fPbool
855 Invalidate buffer-cache for the file prior to starting I/O. Default: true.
858 Use synchronous I/O for buffered writes. For the majority of I/O engines,
859 this means using O_SYNC. Default: false.
861 .BI iomem \fR=\fPstr "\fR,\fP mem" \fR=\fPstr
862 Allocation method for I/O unit buffer. Allowed values are:
867 Allocate memory with \fBmalloc\fR\|(3).
870 Use shared memory buffers allocated through \fBshmget\fR\|(2).
873 Same as \fBshm\fR, but use huge pages as backing.
876 Use \fBmmap\fR\|(2) for allocation. Uses anonymous memory unless a filename
877 is given after the option in the format `:\fIfile\fR'.
880 Same as \fBmmap\fR, but use huge files as backing.
883 The amount of memory allocated is the maximum allowed \fBblocksize\fR for the
884 job multiplied by \fBiodepth\fR. For \fBshmhuge\fR or \fBmmaphuge\fR to work,
885 the system must have free huge pages allocated. \fBmmaphuge\fR also needs to
886 have hugetlbfs mounted, and \fIfile\fR must point there. At least on Linux,
887 huge pages must be manually allocated. See \fB/proc/sys/vm/nr_hugehages\fR
888 and the documentation for that. Normally you just need to echo an appropriate
889 number, eg echoing 8 will ensure that the OS has 8 huge pages ready for
893 .BI iomem_align \fR=\fPint "\fR,\fP mem_align" \fR=\fPint
894 This indicates the memory alignment of the IO memory buffers. Note that the
895 given alignment is applied to the first IO unit buffer, if using \fBiodepth\fR
896 the alignment of the following buffers are given by the \fBbs\fR used. In
897 other words, if using a \fBbs\fR that is a multiple of the page sized in the
898 system, all buffers will be aligned to this value. If using a \fBbs\fR that
899 is not page aligned, the alignment of subsequent IO memory buffers is the
900 sum of the \fBiomem_align\fR and \fBbs\fR used.
902 .BI hugepage\-size \fR=\fPint
903 Defines the size of a huge page. Must be at least equal to the system setting.
904 Should be a multiple of 1MB. Default: 4MB.
907 Terminate all jobs when one finishes. Default: wait for each job to finish.
909 .BI bwavgtime \fR=\fPint
910 Average bandwidth calculations over the given time in milliseconds. Default:
913 .BI iopsavgtime \fR=\fPint
914 Average IOPS calculations over the given time in milliseconds. Default:
917 .BI create_serialize \fR=\fPbool
918 If true, serialize file creation for the jobs. Default: true.
920 .BI create_fsync \fR=\fPbool
921 \fBfsync\fR\|(2) data file after creation. Default: true.
923 .BI create_on_open \fR=\fPbool
924 If true, the files are not created until they are opened for IO by the job.
926 .BI create_only \fR=\fPbool
927 If true, fio will only run the setup phase of the job. If files need to be
928 laid out or updated on disk, only that will be done. The actual job contents
931 .BI pre_read \fR=\fPbool
932 If this is given, files will be pre-read into memory before starting the given
933 IO operation. This will also clear the \fR \fBinvalidate\fR flag, since it is
934 pointless to pre-read and then drop the cache. This will only work for IO
935 engines that are seekable, since they allow you to read the same data
936 multiple times. Thus it will not work on eg network or splice IO.
938 .BI unlink \fR=\fPbool
939 Unlink job files when done. Default: false.
942 Specifies the number of iterations (runs of the same workload) of this job.
945 .BI verify_only \fR=\fPbool
946 Do not perform the specified workload, only verify data still matches previous
947 invocation of this workload. This option allows one to check data multiple
948 times at a later date without overwriting it. This option makes sense only for
949 workloads that write data, and does not support workloads with the
950 \fBtime_based\fR option set.
952 .BI do_verify \fR=\fPbool
953 Run the verify phase after a write phase. Only valid if \fBverify\fR is set.
956 .BI verify \fR=\fPstr
957 Method of verifying file contents after each iteration of the job. Allowed
962 .B md5 crc16 crc32 crc32c crc32c-intel crc64 crc7 sha256 sha512 sha1
963 Store appropriate checksum in the header of each block. crc32c-intel is
964 hardware accelerated SSE4.2 driven, falls back to regular crc32c if
965 not supported by the system.
968 Write extra information about each I/O (timestamp, block number, etc.). The
969 block number is verified. See \fBverify_pattern\fR as well.
972 Pretend to verify. Used for testing internals.
975 This option can be used for repeated burn-in tests of a system to make sure
976 that the written data is also correctly read back. If the data direction given
977 is a read or random read, fio will assume that it should verify a previously
978 written file. If the data direction includes any form of write, the verify will
979 be of the newly written data.
982 .BI verifysort \fR=\fPbool
983 If true, written verify blocks are sorted if \fBfio\fR deems it to be faster to
984 read them back in a sorted manner. Default: true.
986 .BI verifysort_nr \fR=\fPint
987 Pre-load and sort verify blocks for a read workload.
989 .BI verify_offset \fR=\fPint
990 Swap the verification header with data somewhere else in the block before
991 writing. It is swapped back before verifying.
993 .BI verify_interval \fR=\fPint
994 Write the verification header for this number of bytes, which should divide
995 \fBblocksize\fR. Default: \fBblocksize\fR.
997 .BI verify_pattern \fR=\fPstr
998 If set, fio will fill the io buffers with this pattern. Fio defaults to filling
999 with totally random bytes, but sometimes it's interesting to fill with a known
1000 pattern for io verification purposes. Depending on the width of the pattern,
1001 fio will fill 1/2/3/4 bytes of the buffer at the time(it can be either a
1002 decimal or a hex number). The verify_pattern if larger than a 32-bit quantity
1003 has to be a hex number that starts with either "0x" or "0X". Use with
1006 .BI verify_fatal \fR=\fPbool
1007 If true, exit the job on the first observed verification failure. Default:
1010 .BI verify_dump \fR=\fPbool
1011 If set, dump the contents of both the original data block and the data block we
1012 read off disk to files. This allows later analysis to inspect just what kind of
1013 data corruption occurred. Off by default.
1015 .BI verify_async \fR=\fPint
1016 Fio will normally verify IO inline from the submitting thread. This option
1017 takes an integer describing how many async offload threads to create for IO
1018 verification instead, causing fio to offload the duty of verifying IO contents
1019 to one or more separate threads. If using this offload option, even sync IO
1020 engines can benefit from using an \fBiodepth\fR setting higher than 1, as it
1021 allows them to have IO in flight while verifies are running.
1023 .BI verify_async_cpus \fR=\fPstr
1024 Tell fio to set the given CPU affinity on the async IO verification threads.
1025 See \fBcpus_allowed\fP for the format used.
1027 .BI verify_backlog \fR=\fPint
1028 Fio will normally verify the written contents of a job that utilizes verify
1029 once that job has completed. In other words, everything is written then
1030 everything is read back and verified. You may want to verify continually
1031 instead for a variety of reasons. Fio stores the meta data associated with an
1032 IO block in memory, so for large verify workloads, quite a bit of memory would
1033 be used up holding this meta data. If this option is enabled, fio will write
1034 only N blocks before verifying these blocks.
1036 .BI verify_backlog_batch \fR=\fPint
1037 Control how many blocks fio will verify if verify_backlog is set. If not set,
1038 will default to the value of \fBverify_backlog\fR (meaning the entire queue is
1039 read back and verified). If \fBverify_backlog_batch\fR is less than
1040 \fBverify_backlog\fR then not all blocks will be verified, if
1041 \fBverify_backlog_batch\fR is larger than \fBverify_backlog\fR, some blocks
1042 will be verified more than once.
1044 .BI trim_percentage \fR=\fPint
1045 Number of verify blocks to discard/trim.
1047 .BI trim_verify_zero \fR=\fPbool
1048 Verify that trim/discarded blocks are returned as zeroes.
1050 .BI trim_backlog \fR=\fPint
1051 Trim after this number of blocks are written.
1053 .BI trim_backlog_batch \fR=\fPint
1054 Trim this number of IO blocks.
1056 .BI experimental_verify \fR=\fPbool
1057 Enable experimental verification.
1059 .B stonewall "\fR,\fP wait_for_previous"
1060 Wait for preceding jobs in the job file to exit before starting this one.
1061 \fBstonewall\fR implies \fBnew_group\fR.
1064 Start a new reporting group. If not given, all jobs in a file will be part
1065 of the same reporting group, unless separated by a stonewall.
1067 .BI numjobs \fR=\fPint
1068 Number of clones (processes/threads performing the same workload) of this job.
1072 If set, display per-group reports instead of per-job when \fBnumjobs\fR is
1076 Use threads created with \fBpthread_create\fR\|(3) instead of processes created
1077 with \fBfork\fR\|(2).
1079 .BI zonesize \fR=\fPint
1080 Divide file into zones of the specified size in bytes. See \fBzoneskip\fR.
1082 .BI zonerange \fR=\fPint
1083 Give size of an IO zone. See \fBzoneskip\fR.
1085 .BI zoneskip \fR=\fPint
1086 Skip the specified number of bytes when \fBzonesize\fR bytes of data have been
1089 .BI write_iolog \fR=\fPstr
1090 Write the issued I/O patterns to the specified file. Specify a separate file
1091 for each job, otherwise the iologs will be interspersed and the file may be
1094 .BI read_iolog \fR=\fPstr
1095 Replay the I/O patterns contained in the specified file generated by
1096 \fBwrite_iolog\fR, or may be a \fBblktrace\fR binary file.
1098 .BI replay_no_stall \fR=\fPint
1099 While replaying I/O patterns using \fBread_iolog\fR the default behavior
1100 attempts to respect timing information between I/Os. Enabling
1101 \fBreplay_no_stall\fR causes I/Os to be replayed as fast as possible while
1102 still respecting ordering.
1104 .BI replay_redirect \fR=\fPstr
1105 While replaying I/O patterns using \fBread_iolog\fR the default behavior
1106 is to replay the IOPS onto the major/minor device that each IOP was recorded
1107 from. Setting \fBreplay_redirect\fR causes all IOPS to be replayed onto the
1108 single specified device regardless of the device it was recorded from.
1110 .BI write_bw_log \fR=\fPstr
1111 If given, write a bandwidth log of the jobs in this job file. Can be used to
1112 store data of the bandwidth of the jobs in their lifetime. The included
1113 fio_generate_plots script uses gnuplot to turn these text files into nice
1114 graphs. See \fBwrite_lat_log\fR for behaviour of given filename. For this
1115 option, the postfix is _bw.log.
1117 .BI write_lat_log \fR=\fPstr
1118 Same as \fBwrite_bw_log\fR, but writes I/O completion latencies. If no
1119 filename is given with this option, the default filename of "jobname_type.log"
1120 is used. Even if the filename is given, fio will still append the type of log.
1122 .BI write_iops_log \fR=\fPstr
1123 Same as \fBwrite_bw_log\fR, but writes IOPS. If no filename is given with this
1124 option, the default filename of "jobname_type.log" is used. Even if the
1125 filename is given, fio will still append the type of log.
1127 .BI log_avg_msec \fR=\fPint
1128 By default, fio will log an entry in the iops, latency, or bw log for every
1129 IO that completes. When writing to the disk log, that can quickly grow to a
1130 very large size. Setting this option makes fio average the each log entry
1131 over the specified period of time, reducing the resolution of the log.
1134 .BI disable_lat \fR=\fPbool
1135 Disable measurements of total latency numbers. Useful only for cutting
1136 back the number of calls to \fBgettimeofday\fR\|(2), as that does impact performance at
1137 really high IOPS rates. Note that to really get rid of a large amount of these
1138 calls, this option must be used with disable_slat and disable_bw as well.
1140 .BI disable_clat \fR=\fPbool
1141 Disable measurements of completion latency numbers. See \fBdisable_lat\fR.
1143 .BI disable_slat \fR=\fPbool
1144 Disable measurements of submission latency numbers. See \fBdisable_lat\fR.
1146 .BI disable_bw_measurement \fR=\fPbool
1147 Disable measurements of throughput/bandwidth numbers. See \fBdisable_lat\fR.
1149 .BI lockmem \fR=\fPint
1150 Pin the specified amount of memory with \fBmlock\fR\|(2). Can be used to
1151 simulate a smaller amount of memory. The amount specified is per worker.
1153 .BI exec_prerun \fR=\fPstr
1154 Before running the job, execute the specified command with \fBsystem\fR\|(3).
1156 Output is redirected in a file called \fBjobname.prerun.txt\fR
1159 .BI exec_postrun \fR=\fPstr
1160 Same as \fBexec_prerun\fR, but the command is executed after the job completes.
1162 Output is redirected in a file called \fBjobname.postrun.txt\fR
1165 .BI ioscheduler \fR=\fPstr
1166 Attempt to switch the device hosting the file to the specified I/O scheduler.
1168 .BI cpuload \fR=\fPint
1169 If the job is a CPU cycle-eater, attempt to use the specified percentage of
1172 .BI cpuchunks \fR=\fPint
1173 If the job is a CPU cycle-eater, split the load into cycles of the
1174 given time in milliseconds.
1176 .BI disk_util \fR=\fPbool
1177 Generate disk utilization statistics if the platform supports it. Default: true.
1179 .BI clocksource \fR=\fPstr
1180 Use the given clocksource as the base of timing. The supported options are:
1184 \fBgettimeofday\fR\|(2)
1187 \fBclock_gettime\fR\|(2)
1190 Internal CPU clock source
1194 \fBcpu\fR is the preferred clocksource if it is reliable, as it is very fast
1195 (and fio is heavy on time calls). Fio will automatically use this clocksource
1196 if it's supported and considered reliable on the system it is running on,
1197 unless another clocksource is specifically set. For x86/x86-64 CPUs, this
1198 means supporting TSC Invariant.
1200 .BI gtod_reduce \fR=\fPbool
1201 Enable all of the \fBgettimeofday\fR\|(2) reducing options (disable_clat, disable_slat,
1202 disable_bw) plus reduce precision of the timeout somewhat to really shrink the
1203 \fBgettimeofday\fR\|(2) call count. With this option enabled, we only do about 0.4% of
1204 the gtod() calls we would have done if all time keeping was enabled.
1206 .BI gtod_cpu \fR=\fPint
1207 Sometimes it's cheaper to dedicate a single thread of execution to just getting
1208 the current time. Fio (and databases, for instance) are very intensive on
1209 \fBgettimeofday\fR\|(2) calls. With this option, you can set one CPU aside for doing
1210 nothing but logging current time to a shared memory location. Then the other
1211 threads/processes that run IO workloads need only copy that segment, instead of
1212 entering the kernel with a \fBgettimeofday\fR\|(2) call. The CPU set aside for doing
1213 these time calls will be excluded from other uses. Fio will manually clear it
1214 from the CPU mask of other jobs.
1216 .BI ignore_error \fR=\fPstr
1217 Sometimes you want to ignore some errors during test in that case you can specify
1218 error list for each error type.
1220 ignore_error=READ_ERR_LIST,WRITE_ERR_LIST,VERIFY_ERR_LIST
1222 errors for given error type is separated with ':'.
1223 Error may be symbol ('ENOSPC', 'ENOMEM') or an integer.
1225 Example: ignore_error=EAGAIN,ENOSPC:122 .
1227 This option will ignore EAGAIN from READ, and ENOSPC and 122(EDQUOT) from WRITE.
1229 .BI error_dump \fR=\fPbool
1230 If set dump every error even if it is non fatal, true by default. If disabled
1231 only fatal error will be dumped
1233 .BI profile \fR=\fPstr
1234 Select a specific builtin performance test.
1236 .BI cgroup \fR=\fPstr
1237 Add job to this control group. If it doesn't exist, it will be created.
1238 The system must have a mounted cgroup blkio mount point for this to work. If
1239 your system doesn't have it mounted, you can do so with:
1241 # mount \-t cgroup \-o blkio none /cgroup
1243 .BI cgroup_weight \fR=\fPint
1244 Set the weight of the cgroup to this value. See the documentation that comes
1245 with the kernel, allowed values are in the range of 100..1000.
1247 .BI cgroup_nodelete \fR=\fPbool
1248 Normally fio will delete the cgroups it has created after the job completion.
1249 To override this behavior and to leave cgroups around after the job completion,
1250 set cgroup_nodelete=1. This can be useful if one wants to inspect various
1251 cgroup files after job completion. Default: false
1254 Instead of running as the invoking user, set the user ID to this value before
1255 the thread/process does any work.
1258 Set group ID, see \fBuid\fR.
1260 .BI unit_base \fR=\fPint
1261 Base unit for reporting. Allowed values are:
1265 Use auto-detection (default).
1275 .BI flow_id \fR=\fPint
1276 The ID of the flow. If not specified, it defaults to being a global flow. See
1280 Weight in token-based flow control. If this value is used, then there is a
1281 \fBflow counter\fR which is used to regulate the proportion of activity between
1282 two or more jobs. fio attempts to keep this flow counter near zero. The
1283 \fBflow\fR parameter stands for how much should be added or subtracted to the
1284 flow counter on each iteration of the main I/O loop. That is, if one job has
1285 \fBflow=8\fR and another job has \fBflow=-1\fR, then there will be a roughly
1286 1:8 ratio in how much one runs vs the other.
1288 .BI flow_watermark \fR=\fPint
1289 The maximum value that the absolute value of the flow counter is allowed to
1290 reach before the job must wait for a lower value of the counter.
1292 .BI flow_sleep \fR=\fPint
1293 The period of time, in microseconds, to wait after the flow watermark has been
1294 exceeded before retrying operations
1296 .BI clat_percentiles \fR=\fPbool
1297 Enable the reporting of percentiles of completion latencies.
1299 .BI percentile_list \fR=\fPfloat_list
1300 Overwrite the default list of percentiles for completion
1301 latencies. Each number is a floating number in the range (0,100], and
1302 the maximum length of the list is 20. Use ':' to separate the
1303 numbers. For example, \-\-percentile_list=99.5:99.9 will cause fio to
1304 report the values of completion latency below which 99.5% and 99.9% of
1305 the observed latencies fell, respectively.
1306 .SS "Ioengine Parameters List"
1307 Some parameters are only valid when a specific ioengine is in use. These are
1308 used identically to normal parameters, with the caveat that when used on the
1309 command line, the must come after the ioengine that defines them is selected.
1311 .BI (cpu)cpuload \fR=\fPint
1312 Attempt to use the specified percentage of CPU cycles.
1314 .BI (cpu)cpuchunks \fR=\fPint
1315 Split the load into cycles of the given time. In microseconds.
1317 .BI (libaio)userspace_reap
1318 Normally, with the libaio engine in use, fio will use
1319 the io_getevents system call to reap newly returned events.
1320 With this flag turned on, the AIO ring will be read directly
1321 from user-space to reap events. The reaping mode is only
1322 enabled when polling for a minimum of 0 events (eg when
1323 iodepth_batch_complete=0).
1325 .BI (net,netsplice)hostname \fR=\fPstr
1326 The host name or IP address to use for TCP or UDP based IO.
1327 If the job is a TCP listener or UDP reader, the hostname is not
1328 used and must be omitted unless it is a valid UDP multicast address.
1330 .BI (net,netsplice)port \fR=\fPint
1331 The TCP or UDP port to bind to or connect to.
1333 .BI (net,netsplice)interface \fR=\fPstr
1334 The IP address of the network interface used to send or receive UDP multicast
1337 .BI (net,netsplice)ttl \fR=\fPint
1338 Time-to-live value for outgoing UDP multicast packets. Default: 1
1340 .BI (net,netsplice)nodelay \fR=\fPbool
1341 Set TCP_NODELAY on TCP connections.
1343 .BI (net,netsplice)protocol \fR=\fPstr "\fR,\fP proto" \fR=\fPstr
1344 The network protocol to use. Accepted values are:
1349 Transmission control protocol
1352 Transmission control protocol V6
1355 User datagram protocol
1358 User datagram protocol V6
1364 When the protocol is TCP or UDP, the port must also be given,
1365 as well as the hostname if the job is a TCP listener or UDP
1366 reader. For unix sockets, the normal filename option should be
1367 used and the port is invalid.
1370 .BI (net,netsplice)listen
1371 For TCP network connections, tell fio to listen for incoming
1372 connections rather than initiating an outgoing connection. The
1373 hostname must be omitted if this option is used.
1375 .BI (net, pingpong) \fR=\fPbool
1376 Normally a network writer will just continue writing data, and a network reader
1377 will just consume packages. If pingpong=1 is set, a writer will send its normal
1378 payload to the reader, then wait for the reader to send the same payload back.
1379 This allows fio to measure network latencies. The submission and completion
1380 latencies then measure local time spent sending or receiving, and the
1381 completion latency measures how long it took for the other end to receive and
1382 send back. For UDP multicast traffic pingpong=1 should only be set for a single
1383 reader when multiple readers are listening to the same address.
1385 .BI (e4defrag,donorname) \fR=\fPstr
1386 File will be used as a block donor (swap extents between files)
1388 .BI (e4defrag,inplace) \fR=\fPint
1389 Configure donor file block allocation strategy
1392 Preallocate donor's file on init
1395 allocate space immediately inside defragment event, and free right after event
1398 While running, \fBfio\fR will display the status of the created jobs. For
1402 Threads: 1: [_r] [24.8% done] [ 13509/ 8334 kb/s] [eta 00h:01m:31s]
1405 The characters in the first set of brackets denote the current status of each
1406 threads. The possible values are:
1412 Setup but not started.
1418 Initialized, waiting.
1421 Running, doing sequential reads.
1424 Running, doing random reads.
1427 Running, doing sequential writes.
1430 Running, doing random writes.
1433 Running, doing mixed sequential reads/writes.
1436 Running, doing mixed random reads/writes.
1439 Running, currently waiting for \fBfsync\fR\|(2).
1442 Running, verifying written data.
1445 Exited, not reaped by main thread.
1448 Exited, thread reaped.
1452 The second set of brackets shows the estimated completion percentage of
1453 the current group. The third set shows the read and write I/O rate,
1454 respectively. Finally, the estimated run time of the job is displayed.
1456 When \fBfio\fR completes (or is interrupted by Ctrl-C), it will show data
1457 for each thread, each group of threads, and each disk, in that order.
1459 Per-thread statistics first show the threads client number, group-id, and
1460 error code. The remaining figures are as follows:
1464 Number of megabytes of I/O performed.
1467 Average data rate (bandwidth).
1473 Submission latency minimum, maximum, average and standard deviation. This is
1474 the time it took to submit the I/O.
1477 Completion latency minimum, maximum, average and standard deviation. This
1478 is the time between submission and completion.
1481 Bandwidth minimum, maximum, percentage of aggregate bandwidth received, average
1482 and standard deviation.
1485 CPU usage statistics. Includes user and system time, number of context switches
1486 this thread went through and number of major and minor page faults.
1489 Distribution of I/O depths. Each depth includes everything less than (or equal)
1490 to it, but greater than the previous depth.
1493 Number of read/write requests issued, and number of short read/write requests.
1496 Distribution of I/O completion latencies. The numbers follow the same pattern
1500 The group statistics show:
1505 Number of megabytes I/O performed.
1508 Aggregate bandwidth of threads in the group.
1511 Minimum average bandwidth a thread saw.
1514 Maximum average bandwidth a thread saw.
1517 Shortest runtime of threads in the group.
1520 Longest runtime of threads in the group.
1524 Finally, disk statistics are printed with reads first:
1529 Number of I/Os performed by all groups.
1532 Number of merges in the I/O scheduler.
1535 Number of ticks we kept the disk busy.
1538 Total time spent in the disk queue.
1545 It is also possible to get fio to dump the current output while it is
1546 running, without terminating the job. To do that, send fio the \fBUSR1\fR
1549 If the \fB\-\-minimal\fR option is given, the results will be printed in a
1550 semicolon-delimited format suitable for scripted use - a job description
1551 (if provided) follows on a new line. Note that the first
1552 number in the line is the version number. If the output has to be changed
1553 for some reason, this number will be incremented by 1 to signify that
1554 change. The fields are:
1557 .B terse version, fio version, jobname, groupid, error
1561 .B Total I/O \fR(KB)\fP, bandwidth \fR(KB/s)\fP, IOPS, runtime \fR(ms)\fP
1565 .B min, max, mean, standard deviation
1569 .B min, max, mean, standard deviation
1571 Completion latency percentiles (20 fields):
1573 .B Xth percentile=usec
1577 .B min, max, mean, standard deviation
1581 .B min, max, aggregate percentage of total, mean, standard deviation
1587 .B Total I/O \fR(KB)\fP, bandwidth \fR(KB/s)\fP, IOPS, runtime \fR(ms)\fP
1591 .B min, max, mean, standard deviation
1595 .B min, max, mean, standard deviation
1597 Completion latency percentiles (20 fields):
1599 .B Xth percentile=usec
1603 .B min, max, mean, standard deviation
1607 .B min, max, aggregate percentage of total, mean, standard deviation
1613 .B user, system, context switches, major page faults, minor page faults
1616 IO depth distribution:
1618 .B <=1, 2, 4, 8, 16, 32, >=64
1621 IO latency distribution:
1625 .B <=2, 4, 10, 20, 50, 100, 250, 500, 750, 1000
1629 .B <=2, 4, 10, 20, 50, 100, 250, 500, 750, 1000, 2000, >=2000
1633 Disk utilization (1 for each disk used):
1635 .B name, read ios, write ios, read merges, write merges, read ticks, write ticks, read in-queue time, write in-queue time, disk utilization percentage
1638 Error Info (dependent on continue_on_error, default off):
1640 .B total # errors, first error code
1643 .B text description (if provided in config - appears on newline)
1646 Normally you would run fio as a stand-alone application on the machine
1647 where the IO workload should be generated. However, it is also possible to
1648 run the frontend and backend of fio separately. This makes it possible to
1649 have a fio server running on the machine(s) where the IO workload should
1650 be running, while controlling it from another machine.
1652 To start the server, you would do:
1654 \fBfio \-\-server=args\fR
1656 on that machine, where args defines what fio listens to. The arguments
1657 are of the form 'type:hostname or IP:port'. 'type' is either 'ip' (or ip4)
1658 for TCP/IP v4, 'ip6' for TCP/IP v6, or 'sock' for a local unix domain
1659 socket. 'hostname' is either a hostname or IP address, and 'port' is the port to
1660 listen to (only valid for TCP/IP, not a local socket). Some examples:
1664 Start a fio server, listening on all interfaces on the default port (8765).
1666 2) fio \-\-server=ip:hostname,4444
1668 Start a fio server, listening on IP belonging to hostname and on port 4444.
1670 3) fio \-\-server=ip6:::1,4444
1672 Start a fio server, listening on IPv6 localhost ::1 and on port 4444.
1674 4) fio \-\-server=,4444
1676 Start a fio server, listening on all interfaces on port 4444.
1678 5) fio \-\-server=1.2.3.4
1680 Start a fio server, listening on IP 1.2.3.4 on the default port.
1682 6) fio \-\-server=sock:/tmp/fio.sock
1684 Start a fio server, listening on the local socket /tmp/fio.sock.
1686 When a server is running, you can connect to it from a client. The client
1689 fio \-\-local-args \-\-client=server \-\-remote-args <job file(s)>
1691 where \-\-local-args are arguments that are local to the client where it is
1692 running, 'server' is the connect string, and \-\-remote-args and <job file(s)>
1693 are sent to the server. The 'server' string follows the same format as it
1694 does on the server side, to allow IP/hostname/socket and port strings.
1695 You can connect to multiple clients as well, to do that you could run:
1697 fio \-\-client=server2 \-\-client=server2 <job file(s)>
1701 was written by Jens Axboe <jens.axboe@oracle.com>,
1702 now Jens Axboe <jaxboe@fusionio.com>.
1704 This man page was written by Aaron Carroll <aaronc@cse.unsw.edu.au> based
1705 on documentation by Jens Axboe.
1706 .SH "REPORTING BUGS"
1707 Report bugs to the \fBfio\fR mailing list <fio@vger.kernel.org>.
1710 For further documentation see \fBHOWTO\fR and \fBREADME\fR.
1712 Sample jobfiles are available in the \fBexamples\fR directory.
projects / fio.git / blob