$ fio --name=random-writers --ioengine=libaio --iodepth=4 --rw=randwrite --bs=32k --direct=0 --size=64m --numjobs=4
+4.1 Environment variables
+-------------------------
+
fio also supports environment variable expansion in job files. Any
substring of the form "${VARNAME}" as part of an option value (in other
words, on the right of the `='), will be expanded to the value of the
fio ships with a few example job files, you can also look there for
inspiration.
+4.2 Reserved keywords
+---------------------
+
+Additionally, fio has a set of reserved keywords that will be replaced
+internally with the appropriate value. Those keywords are:
+
+$pagesize The architecture page size of the running system
+$mb_memory Megabytes of total memory in the system
+$ncpus Number of online available CPUs
+
+These can be used on the command line or in the job file, and will be
+automatically substituted with the current system values when the job
+is run.
+
5.0 Detailed list of parameters
-------------------------------
a string. The following types are used:
str String. This is a sequence of alpha characters.
-time Integer with possible time postfix. In seconds unless otherwise
+time Integer with possible time suffix. In seconds unless otherwise
specified, use eg 10m for 10 minutes. Accepts s/m/h for seconds,
minutes, and hours.
-int SI integer. A whole number value, which may contain a postfix
- describing the base of the number. Accepted postfixes are k/m/g,
- 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 separate such values. May also include a prefix
- to indicate numbers base. If 0x is used, the number is assumed to
- be hexadecimal. See irange.
+int SI integer. A whole number value, which may contain a suffix
+ describing the base of the number. Accepted suffixes are k/m/g/t/p,
+ meaning kilo, mega, giga, tera, and peta. The suffix is not case
+ sensitive. So if you want to specify 4096, you could either write
+ out '4096' or just give 4k. The suffixes 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 separate such values.
+ May also include a prefix to indicate numbers base. If 0x is used,
+ the number is assumed to be hexadecimal. 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
+irange Integer range with suffix. Allows value range to be given, such
as 1024-4096. A colon may also be used as the separator, eg
1k:4k. If the option allows two sets of ranges, they can be
specified with a ',' or '/' delimiter: 1k-4k/8k-32k. Also see
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
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
+ filename=/dev/sda:/dev/sdb. If the wanted filename does need to
+ include a colon, then escape that with a '\' character. For
+ instance, if the filename is "/dev/dsk/foo@3,0:c", then you would
+ use filename="/dev/dsk/foo@3,0\:c". '-' 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
IO's, instead of for every IO. Use rw=randread:8 to specify
that.
+kb_base=int The base unit for a kilobyte. The defacto base is 2^10, 1024.
+ Storage manufacturers like to use 10^3 or 1000 as a base
+ ten unit instead, for obvious reasons. Allow values are
+ 1024 or 1000, with 1024 being the default.
+
randrepeat=bool For random IO workloads, seed the generator in a predictable
way so that results are repeatable across repetitions.
after every block.
rate=int Cap the bandwidth used by this job. The number is in bytes/sec,
- the normal postfix rules apply. You can use rate=500k to limit
+ the normal suffix rules apply. You can use rate=500k to limit
reads and writes to 500k each, or you can specify read and
writes separately. Using rate=1m,500k would limit reads to
1MB/sec and writes to 500KB/sec. Capping only reads or
sha256 Use sha256 as the checksum function.
+ sha1 Use optimized sha1 as the checksum function.
+
meta Write extra information about each io
(timestamp, block number etc.). The block
number is verified.
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.
+ correctly read back. If the data direction given is
+ a read or random read, fio will assume that it should
+ verify a previously written file. If the data direction
+ includes any form of write, the verify will be of the
+ newly written data.
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