[disktools.git] / README.fio

fio
---

fio is a tool that will spawn a number of thread doing a particular
type of io action as specified by the user. fio takes a number of
global parameters, each inherited by the thread unless otherwise
parameters given to them overriding that setting is given.

Options
-------

$ fio
	-s IO is sequential
	-b block size in KiB for each io
	-t <sec> Runtime in seconds
	-r For random io, sequence must be repeatable
	-R <on> If one thread fails to meet rate, quit all
	-o <on> Use direct IO is 1, buffered if 0
	-l Generate per-job latency logs
	-w Generate per-job bandwidth logs
	-f <file> Read <file> for job descriptions

	<jobs>

The <jobs> format is as follows:

	rw=0/1		0 is read, 1 is write
	prio=x		Run io at prio X, 0-7 is the kernel allowed range
	prioclass=x	Run io at prio class X
	file=foo	Do the io to file foo
	bs=x		Thread blocksize is x KiB
	direct=x	1 for direct IO, 0 for buffered IO
	delay=x		Delay x useconds before each io
	random		IO is randomized
	sequential	IO is sequential
	rate=x		Throttle rate to x KiB/sec
	ratemin=x	Quit if rate of x KiB/sec can't be met
	ratecycle=x	ratemin averaged over x msecs
	cpumask=x	Allow job to run on CPUs defined by mask
	fsync=x		If writing, fsync after every x blocks have been written
	startdelay=x	Start this thread x seconds after startup
	timeout=x	Terminate x seconds after startup
	aio		Use Linux async io
	aio_depth=x	Allow x iocbs in flight
	size=x		Set file size to x bytes (x string can include k/m/g)
	offset=x	Start io at offset x (x string can include k/m/g)
	invalidate=x	Invalidate page cache for file prior to doing io
	sync=x		Use sync writes if x and writing
	mem=x		If x == malloc, use malloc for buffers. If x == shm,
			use shm for buffers.


Examples using cmd line jobs
----------------------------

Spawn 2 threads, one read and one writer. Both threads want direct and
sequential io, set these as global options. The reader wants a 4kb block
size and the writer a 16kb block size, set those as thread options.

$ fio -o1 -s "{rw=0,file=read_file,bs=4096}" "{rw=1,file=write_file,bs=16384}"

Spawn 3 reader threads doing io at priorities 0, 3, and 6. The highest
prio thread wants direct io, the others buffered. All want a 4kb block
size.

$ fio -o0 -s -b4096 "{rw=0,file=rf1,prio=6}" "{rw=0,file=rf2,prio=3}" "{rw=0,file=rf3,prio=0,direct=1}"

Examples using a job file
-------------------------

A sample job file doing the same as above would look like this:

[read_file]
rw=0
bs=4096

[write_file]
rw=1
bs=16384

And fio would be invoked as:

$ fio -o1 -s -f file_with_above

The second example would look like this:

[rf1]
rw=0
prio=6

[rf2]
rw=0
prio=3

[rf3]
rw=0
prio=0
direct=1

And fio would be invoked as:

$ fio -o0 -s -b4096 -f file_with_above

'global' is a reserved keyword. When used as the filename, it sets the
default options for the threads following that section. It is possible
to have more than one global section in the file, as it only affects
subsequent jobs.

Also see the examples/ dir for sample job files.
Commit	Line	Data
e709787c JA	1	fio
	2	---
	3
	4	fio is a tool that will spawn a number of thread doing a particular
	5	type of io action as specified by the user. fio takes a number of
	6	global parameters, each inherited by the thread unless otherwise
	7	parameters given to them overriding that setting is given.
	8
	9	Options
	10	-------
	11
	12	$ fio
	13	-s IO is sequential
86184d14	14	-b block size in KiB for each io
e709787c	15	-t <sec> Runtime in seconds
e709787c	16	-r For random io, sequence must be repeatable
02bdd9ba	17	-R <on> If one thread fails to meet rate, quit all
e709787c	18	-o <on> Use direct IO is 1, buffered if 0
a0a9b35b JA	19	-l Generate per-job latency logs
a0a9b35b JA	20	-w Generate per-job bandwidth logs
7dd1389e	21	-f <file> Read <file> for job descriptions
e709787c JA	22
	23	<jobs>
	24
	25	The <jobs> format is as follows:
	26
	27	rw=0/1 0 is read, 1 is write
	28	prio=x Run io at prio X, 0-7 is the kernel allowed range
	29	prioclass=x Run io at prio class X
	30	file=foo Do the io to file foo
86184d14	31	bs=x Thread blocksize is x KiB
e709787c JA	32	direct=x 1 for direct IO, 0 for buffered IO
	33	delay=x Delay x useconds before each io
	34	random IO is randomized
	35	sequential IO is sequential
86184d14	36	rate=x Throttle rate to x KiB/sec
4240cfa1 JA	37	ratemin=x Quit if rate of x KiB/sec can't be met
4240cfa1 JA	38	ratecycle=x ratemin averaged over x msecs
18e0b78c	39	cpumask=x Allow job to run on CPUs defined by mask
4240cfa1	40	fsync=x If writing, fsync after every x blocks have been written
fc24389f	41	startdelay=x Start this thread x seconds after startup
67903a2e	42	timeout=x Terminate x seconds after startup
43000118 JA	43	aio Use Linux async io
43000118 JA	44	aio_depth=x Allow x iocbs in flight
02983297 JA	45	size=x Set file size to x bytes (x string can include k/m/g)
02983297 JA	46	offset=x Start io at offset x (x string can include k/m/g)
b95799ca	47	invalidate=x Invalidate page cache for file prior to doing io
74b4b5fb	48	sync=x Use sync writes if x and writing
99c6704f JA	49	mem=x If x == malloc, use malloc for buffers. If x == shm,
99c6704f JA	50	use shm for buffers.
e709787c JA	51
e709787c JA	52
7dd1389e JA	53	Examples using cmd line jobs
7dd1389e JA	54	----------------------------
e709787c JA	55
	56	Spawn 2 threads, one read and one writer. Both threads want direct and
	57	sequential io, set these as global options. The reader wants a 4kb block
	58	size and the writer a 16kb block size, set those as thread options.
	59
	60	$ fio -o1 -s "{rw=0,file=read_file,bs=4096}" "{rw=1,file=write_file,bs=16384}"
	61
	62	Spawn 3 reader threads doing io at priorities 0, 3, and 6. The highest
	63	prio thread wants direct io, the others buffered. All want a 4kb block
	64	size.
	65
	66	$ fio -o0 -s -b4096 "{rw=0,file=rf1,prio=6}" "{rw=0,file=rf2,prio=3}" "{rw=0,file=rf3,prio=0,direct=1}"
	67
7dd1389e JA	68	Examples using a job file
	69	-------------------------
	70
	71	A sample job file doing the same as above would look like this:
	72
	73	[read_file]
	74	rw=0
	75	bs=4096
	76
	77	[write_file]
	78	rw=1
	79	bs=16384
	80
	81	And fio would be invoked as:
	82
	83	$ fio -o1 -s -f file_with_above
	84
	85	The second example would look like this:
	86
	87	[rf1]
	88	rw=0
	89	prio=6
	90
	91	[rf2]
	92	rw=0
	93	prio=3
	94
	95	[rf3]
	96	rw=0
	97	prio=0
	98	direct=1
	99
	100	And fio would be invoked as:
	101
	102	$ fio -o0 -s -b4096 -f file_with_above
	103
47d45203 JA	104	'global' is a reserved keyword. When used as the filename, it sets the
	105	default options for the threads following that section. It is possible
	106	to have more than one global section in the file, as it only affects
	107	subsequent jobs.
ed864e24 JA	108
ed864e24 JA	109	Also see the examples/ dir for sample job files.
47d45203	110