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
cpumask=int Set the CPU affinity of this job. The parameter given is a
bitmask of allowed CPU's the job may run on. See man
- sched_setaffinity(2).
+ sched_setaffinity(2). This may not work on all supported
+ operating systems or kernel versions.
startdelay=int Start this job the specified number of seconds after fio
has started. Only useful if the job file contains several
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.
read_iolog=str Open an iolog with the specified file name and replay the
io patterns it contains. This can be used to store a
- workload and replay it sometime later.
+ workload and replay it sometime later. The iolog given
+ may also be a blktrace binary file, which allows fio
+ to replay a workload captured by blktrace. See blktrace
+ for how to capture such logging data. For blktrace replay,
+ the file needs to be turned into a blkparse binary data
+ file first (blktrace <device> -d file_for_fio.bin).
write_bw_log If given, write a bandwidth log of the jobs in this job
file. Can be used to store data of the bandwidth of the
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%
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,