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.
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
- postfix is used with a sequential IO pattern, then the value
+ 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.
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
channel semantics (Send/Recv) for the
InfiniBand, RoCE and iWARP protocols.
+ falloc IO engine that does regular fallocate to
+ simulate data transfer as fio ioengine.
+ DDIR_READ does fallocate(,mode = keep_size,)
+ DDIR_WRITE does fallocate(,mode = 0)
+ DDIR_TRIM does fallocate(,mode = punch_hole)
+
+ e4defrag IO engine that does regular EXT4_IOC_MOVE_EXT
+ ioctls to simulate defragment activity in
+ request to DDIR_WRITE event
+
external Prefix to specify loading an external
IO engine object file. Append the engine
filename, eg ioengine=external:/tmp/foo.o
the job to exit. The same format as rate is used for read vs
write seperation.
+max_latency=int If set, fio will exit the job if it exceeds this maximum
+ latency. It will exit with an ETIME error.
+
ratecycle=int Average bandwidth for 'rate' and 'ratemin' over this number
of milliseconds.
allows a range of CPUs. Say you wanted a binding to CPUs
1, 5, and 8-15, you would set cpus_allowed=1,5,8-15.
+numa_cpu_nodes=str Set this job running on spcified NUMA nodes' CPUs. The
+ arguments allow comma delimited list of cpu numbers,
+ A-B ranges, or 'all'. Note, to enable numa options support,
+ export the following environment variables,
+ export EXTFLAGS+=" -DFIO_HAVE_LIBNUMA "
+ export EXTLIBS+=" -lnuma "
+
+numa_mem_policy=str Set this job's memory policy and corresponding NUMA
+ nodes. Format of the argements:
+ <mode>[:<nodelist>]
+ `mode' is one of the following memory policy:
+ default, prefer, bind, interleave, local
+ For `default' and `local' memory policy, no node is
+ needed to be specified.
+ For `prefer', only one node is allowed.
+ For `bind' and `interleave', it allow comma delimited
+ list of numbers, A-B ranges, or 'all'.
+
startdelay=time Start this job the specified number of seconds after fio
has started. Only useful if the job file contains several
jobs, and you want to delay starting some jobs to a certain
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
points in the job file. A stone wall also implies starting
a new reporting group.
-new_group Start a new reporting group. If this option isn't given,
- jobs in a file will be part of the same reporting group
- unless separated by a stone wall (or if it's a group
- by itself, with the numjobs option).
+new_group Start a new reporting group. See: group_reporting.
numjobs=int Create the specified number of clones of this job. May be
used to setup a larger number of threads/processes doing
- the same thing. We regard that grouping of jobs as a
- specific group.
-
-group_reporting If 'numjobs' is set, it may be interesting to display
- statistics for the group as a whole instead of for each
- individual job. This is especially true of 'numjobs' is
- large, looking at individual thread/process output quickly
- becomes unwieldy. If 'group_reporting' is specified, fio
- will show the final report per-group instead of per-job.
+ the same thing. Each thread is reported separately; to see
+ statistics for all clones as a whole, use group_reporting in
+ conjunction with new_group.
+
+group_reporting It may sometimes be interesting to display statistics for
+ groups of jobs as a whole instead of for each individual job.
+ This is especially true if 'numjobs' is used; looking at
+ individual thread/process output quickly becomes unwieldy.
+ To see the final report per-group instead of per-job, use
+ 'group_reporting'. Jobs in a file will be part of the same
+ reporting group, unless if separated by a stonewall, or by
+ using 'new_group'.
thread fio defaults to forking jobs, however if this option is
given, fio will use pthread_create(3) to create threads
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
submission, completion, and total latencies instead. If no
1 Backward-compatible alias for 'all'.
+ignore_error=str Sometimes you want to ignore some errors during test
+ in that case you can specify error list for each error type.
+ ignore_error=READ_ERR_LIST,WRITE_ERR_LIST,VERIFY_ERR_LIST
+ errors for given error type is separated with ':'. Error
+ may be symbol ('ENOSPC', 'ENOMEM') or integer.
+ Example:
+ ignore_error=EAGAIN,ENOSPC:122
+ This option will ignore EAGAIN from READ, and ENOSPC and
+ 122(EDQUOT) from WRITE.
+
+error_dump=bool If set dump every error even if it is non fatal, true
+ by default. If disabled only fatal error will be dumped
+
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
[net] proto=str The network protocol to use. Accepted values are:
tcp Transmission control protocol
- udp Unreliable datagram protocol
+ udp User datagram protocol
unix UNIX domain socket
When the protocol is TCP or UDP, the port must also be given,
[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.
+[e4defrag] donorname=str
+ File will be used as a block donor(swap extents between files)
+[e4defrag] inplace=int
+ Configure donor file blocks allocation strategy
+ 0(default): Preallocate donor's file on init
+ 1 : allocate space immidietly inside defragment event,
+ and free right after event
+
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
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,
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
----------------
terse version, fio version, jobname, groupid, error
READ status:
Total IO (KB), bandwidth (KB/sec), IOPS, runtime (msec)
- Submission latency: min, max, mean, deviation
- Completion latency: min, max, mean, deviation
+ 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
- Bw: min, max, aggregate percentage of total, mean, deviation
+ Total latency: min, max, mean, deviation (usec)
+ Bw (KB/s): min, max, aggregate percentage of total, mean, deviation
WRITE status:
Total IO (KB), bandwidth (KB/sec), IOPS, runtime (msec)
- Submission latency: min, max, mean, deviation
- Completion latency: min, max, mean, deviation
+ 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
- Bw: min, max, aggregate percentage of total, mean, deviation
+ 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 microseconds: <=2, 4, 10, 20, 50, 100, 250, 500, 750, 1000