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 seperate such values. 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
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 and
- port to connect to in the format of =host:port.
-
+ port to connect to in the format of =host/port. If the
+ ioengine is file based, you can specify a number of files
+ by seperating 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.
+
+opendir=str Tell fio to recursively add any file it can find in this
+ directory and down the file system tree.
+
+readwrite=str
rw=str Type of io pattern. Accepted values are:
read Sequential reads
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.
+ 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
+ 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.
randrepeat=bool For random IO workloads, seed the generator in a predictable
way so that results are repeatable across repetitions.
+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
+ kernel about it, in which case you can disable this option.
+ If set, fio will use POSIX_FADV_SEQUENTIAL for sequential
+ IO and POSIX_FADV_RANDOM for random IO.
+
size=siint The total size of file io for this job. This may describe
the size of the single file the job uses, or it may be
divided between the number of files in the job. If the
size if larger than the current file size. If this parameter
is not given and the file exists, the file size will be used.
+filesize=siint 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.
+
+blocksize=siint
bs=siint The block size used for the io units. Defaults to 4k. Values
can be given for both read and writes. If a single siint is
given, it will apply to both. If a second siint is specified
can do so by passing an empty read size - bs=,8k will set
8k for writes and leave the read default value.
+blocksize_range=irange
bsrange=irange Instead of giving a single block size, specify a range
and fio will mix the issued io block sizes. The issued
io unit will always be a multiple of the minimum value
writes, however a second range can be given after a comma.
See bs=.
+blocksize_unaligned
bs_unaligned If this option is given, any byte size value within bsrange
may be used as a block range. This typically wont work with
direct IO, as that normally requires sector alignment.
+zero_buffers If this option is given, fio will init the IO buffers to
+ all zeroes. The default is to fill them with random data.
+
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
+ the same as nrfiles, can be set smaller to limit the number
+ simultaneous opens.
+
file_service_type=str Defines how fio decides which file from a job to
service next. The following types are defined:
roundrobin Round robin over open files. This
is the default.
+ The string can have a number appended, indicating how
+ often to switch to a new file. So if option random:4 is
+ given, fio will switch to a new random file after 4 ios
+ have been issued.
+
ioengine=str Defines how the job issues io to the file. The following
types are defined:
net Transfer over the network to given host:port.
'filename' must be set appropriately to
- filename=host:port regardless of send
+ filename=host/port regardless of send
or receive, if the latter only the port
argument is used.
+ cpu Doesn't transfer any data, but burns CPU
+ cycles according to the cpuload= and
+ cpucycle= options. Setting cpuload=85
+ will cause that job to do nothing but burn
+ 85% of the CPU.
+
+ guasi The GUASI IO engine is the Generic Userspace
+ Asyncronous Syscall Interface approach
+ to async IO. See
+
+ http://www.xmailserver.org/guasi-lib.html
+
+ for more info on GUASI.
+
external Prefix to specify loading an external
IO engine object file. Append the engine
filename, eg ioengine=external:/tmp/foo.o
end_fsync=bool If true, fsync file contents when the job exits.
+fsync_on_close=bool If true, fio will fsync() a dirty file on close.
+ This differs from end_fsync in that it will happen on every
+ file close, not just at the end of the job.
+
rwmixcycle=int Value in milliseconds describing how often to switch between
reads and writes for a mixed workload. The default is
500 msecs.
rate=int Cap the bandwidth used by this job to this number of KiB/sec.
ratemin=int Tell fio to do whatever it can to maintain at least this
- bandwidth.
+ bandwidth. Failing to meet this requirement, will cause
+ the job to exit.
+
+rate_iops=int Cap the bandwidth to this number of IOPS. Basically the same
+ as rate, just specified independently of bandwidth. If the
+ job is given a block size range instead of a fixed value,
+ the smallest block size is used as the metric.
+
+rate_iops_min=int If fio doesn't meet this rate of IO, it will cause
+ the job to exit.
ratecycle=int Average bandwidth for 'rate' and 'ratemin' over this number
of milliseconds.
a specified job will run, so this parameter is handy to
cap the total runtime to a given time.
+time_based If set, fio will run for the duration of the runtime
+ specified even if the file(s) are completey read or
+ written. It will simply loop over the same workload
+ as many times as the runtime allows.
+
invalidate=bool Invalidate the buffer/page cache parts for this file prior
to starting io. Defaults to true.
sync=bool Use sync io for buffered writes. For the majority of the
io engines, this means using O_SYNC.
+iomem=str
mem=str Fio can use various types of memory as the io unit buffer.
The allowed values are:
crc32 Use a crc32 sum of the data area and store
it in the header of each block.
+ null Only pretend to verify. Useful for testing
+ internals with ioengine=null, not for much
+ else.
+
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.
+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
+ often the case when overwriting an existing file, since
+ the blocks are already laid out in the file system. You
+ can ignore this option unless doing huge amounts of really
+ fast IO where the red-black tree sorting CPU time becomes
+ significant.
+
stonewall 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.
+ 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 seperated by a stone wall (or if it's a group
+ by itself, with the numjobs option).
numjobs=int Create the specified number of clones of this job. May be
used to setup a larger number of threads/processes doing
cpuchunks=int If the job is a CPU cycle eater, split the load into
cycles of the given time. In milliseconds.
+disk_util=bool Generate disk utilization statistics, if the platform
+ supports it. Defaults to on.
+
6.0 Interpreting the output
---------------------------
bw (KiB/s) : min= 0, max= 1196, per=51.00%, avg=664.02, stdev=681.68
cpu : usr=1.49%, sys=0.25%, ctx=7969
IO depths : 1=0.1%, 2=0.3%, 4=0.5%, 8=99.0%, 16=0.0%, 32=0.0%, >32=0.0%
+ issued r/w: total=0/32768, short=0/0
lat (msec): 2=1.6%, 4=0.0%, 10=3.2%, 20=12.8%, 50=38.4%, 100=24.8%,
lat (msec): 250=15.2%, 500=0.0%, 750=0.0%, 1000=0.0%, >=2048=0.0%
io= Number of megabytes io performed
bw= Average bandwidth rate
runt= The runtime of that thread
- slat= Submission latency (avg being the average, dev being the
+ slat= Submission latency (avg being the average, stdev being the
standard deviation). This is the time it took to submit
the io. For sync io, the slat is really the completion
latency, since queue/complete is one operation there.
16= entries includes depths up to that value but higher
than the previous entry. In other words, it covers the
range from 16 to 31.
+IO issued= The number of read/write requests issued, and how many
+ of them were short.
IO latencies= The distribution of IO completion latencies. This is the
time from when IO leaves fio and when it gets completed.
The numbers follow the same pattern as the IO depths,
----------------
For scripted usage where you typically want to generate tables or graphs
-of the results, fio can output the results in a comma separated format.
+of the results, fio can output the results in a semicolon separated format.
The format is one long line of values, such as:
-client1,0,0,936,331,2894,0,0,0.000000,0.000000,1,170,22.115385,34.290410,16,714,84.252874%,366.500000,566.417819,3496,1237,2894,0,0,0.000000,0.000000,0,246,6.671625,21.436952,0,2534,55.465300%,1406.600000,2008.044216,0.000000%,0.431928%,1109
+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%
Split up, the format is as follows:
projects / fio.git / blobdiff