randrepeat=bool For random IO workloads, seed the generator in a predictable
way so that results are repeatable across repetitions.
+randseed=int Seed the random number generators based on this seed value, to
+ be able to control what sequence of output is being generated.
+ If not set, the random sequence depends on the randrepeat
+ setting.
+
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
may be used as a block range. This typically wont work with
direct IO, as that normally requires sector alignment.
+bs_is_seq_rand If this option is set, fio will use the normal read,write
+ blocksize settings as sequential,random instead. Any random
+ read or write will use the WRITE blocksize settings, and any
+ sequential read or write will use the READ blocksize setting.
+
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.
alternate random and zeroed data throughout the IO
buffer.
+buffer_pattern=str If set, fio will fill the io buffers with this pattern.
+ If not set, the contents of io buffers is defined by the other
+ options related to buffer contents. The setting can be any
+ pattern of bytes, and can be prefixed with 0x for hex values.
+
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
O_DIRECT. Note that ZFS on Solaris doesn't support direct io.
On Windows the synchronous ioengines don't support direct io.
+atomic=bool If value is true, attempt to use atomic direct IO. Atomic
+ writes are guaranteed to be stable once acknowledged by
+ the operating system. Only Linux supports O_ATOMIC right
+ now.
+
buffered=bool If value is true, use buffered io. This is the opposite
of the 'direct' option. Defaults to true.
which are intended to operate on a file in parallel in disjoint
segments, with even spacing between the starting points.
+number_ios=int Fio will normally perform IOs until it has exhausted the size
+ of the region set by size=, or if it exhaust the allocated
+ time (or hits an error condition). With this setting, the
+ range/size can be set independently of the number of IOs to
+ perform. When fio reaches this number, it will exit normally
+ and report status.
+
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
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. The same format
- as rate is used for read vs write seperation.
+ as rate is used for read vs write separation.
rate_iops_min=int If fio doesn't meet this rate of IO, it will cause
the job to exit. The same format as rate is used for read vs
- write seperation.
+ write separation.
+
+latency_target=int If set, fio will attempt to find the max performance
+ point that the given workload will run at while maintaining a
+ latency below this target. The values is given in microseconds.
+ See latency_window and latency_percentile
+
+latency_window=int Used with latency_target to specify the sample window
+ that the job is run at varying queue depths to test the
+ performance. The value is given in microseconds.
+
+latency_percentile=float The percentage of IOs that must fall within the
+ criteria specified by latency_target and latency_window. If not
+ set, this defaults to 100.0, meaning that all IOs must be equal
+ or below to the value set by latency_target.
max_latency=int If set, fio will exit the job if it exceeds this maximum
latency. It will exit with an ETIME error.
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
blocks will be verified more than once.
stonewall
-wait_for_previous Wait for preceeding jobs in the job file to exit, before
+wait_for_previous Wait for preceding 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.
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
+ undesirable 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
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,
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 (dependent on continue_on_error, default off): total # errors, first error code
- Additional Info (dependant on description being set): Text description
+ Additional Info (dependent 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:
projects / fio.git / blobdiff