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
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. See the
- 'rw_sequencer' option.
+ passing in an offset modifier with a value of 8. If the
+ postfix 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
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.
+
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 also has a sub-option,
+ userspace_reap. To set it, use
+ ioengine=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).
posixaio glibc posix asynchronous io.
for more info on GUASI.
rdma The RDMA I/O engine supports both RDMA
- memory semantic(RDMA_WRITE/RDMA_READ) and
- channel semantic(Send/Recv) in InfiniBand, RoCE
- and iWarp environment.
+ 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
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
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.
+
lockmem=int Pin down the specified amount of memory with mlock(2). Can
potentially be used instead of removing memory or booting
with less memory to simulate a smaller amount of memory.
Split up, the format is as follows:
- version, jobname, groupid, error
+ terse version, fio version, jobname, groupid, error
READ status:
- KB IO, bandwidth (KB/sec), runtime (msec)
+ Total IO (KB), bandwidth (KB/sec), IOPS, runtime (msec)
Submission latency: min, max, mean, deviation
Completion latency: min, max, mean, deviation
+ Completion latency percentiles: 20 fields (see below)
Total latency: min, max, mean, deviation
Bw: min, max, aggregate percentage of total, mean, deviation
WRITE status:
- KB IO, bandwidth (KB/sec), runtime (msec)
+ Total IO (KB), bandwidth (KB/sec), IOPS, runtime (msec)
Submission latency: min, max, mean, deviation
Completion latency: min, max, mean, deviation
+ Completion latency percentiles: 20 fields (see below)
Total latency: min, max, mean, deviation
Bw: 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
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
---------------------
projects / fio.git / blobdiff