NAME

ioping - simple disk I/O latency monitoring tool

SYNOPSYS

ioping [-ABCDJLNRWGYykq] [-a count] [-b count] [-c count] [-e seed] [-i interval] [-l speed] [-r rate] [-t time] [-T time] [-s size] [-S wsize] [-o offset] [-w deadline] [-p period] [-P period] [-I [format]] directory|file|device

ioping -h | -v

DESCRIPTION

This tool generates various I/O patterns and lets you monitor I/O speed and latency in real time.

OPTIONS

-a, -warmup count: Ignore in statistics first count requests, default 1. First request usually is much slower due to power-saving features.
-b, -burst count: Make series of count requests without delay, default 0. Aggressive power-saving features slow down requests even after short delay.
-c, -count count: Stop after count requests, default 0 (infinite).
-e, -entropy seed: Set seed for random number generator, default 0 (random).
-i, -interval time: Set time between requests, default 1s.
-l, -speed-limit size: Set speed limit in size per second. Increases interval to request-size / speed.
-r, -rate-limit count: Set rate limit in count per second. Increases interval to 1 / rate.
-t, -min-time time: Minimal valid request time (0us). Too fast requests are ignored in statistics.
-T, -max-time time: Maximum valid request time. Too slow requests are ignored in statistics.
-s, -size size: Request size, default 4k.
-S, -work-size size: Working set size (1m for directory, whole size for file or device).
-o, -work-offset size: Starting offset in the file/device (0).
-w, -work-time time: Stop after time passed, default 0 (infinite).
-p, -print-count count: Print raw statistics for every count requests (see format below).
-P, -print-interval time: Print raw statistics for every time.
-A, -async: Use asynchronous I/O (io_setup(2), io_submit(2) etc syscalls).
-B, -batch: Batch mode. Be quiet and print final statistics in raw format.
-C, -cached: Use cached I/O. Suppress cache invalidation via posix_fadvise(2)) before read and fdatasync(2) after each write.
-D, -direct: Use direct I/O (see O_DIRECT in open(2)).
-I, -time [format]: Print current time for each request. Optional argument defines time format in strftime(3) notation, default is "%b %d %T" (Jan 01 00:00:00).
-J, -json: Print output in JSON format.
-L, -linear: Use sequential operations rather than random. This also sets default request size to 256k (as in -size 256k).
-N, -nowait: Set RWF_NOWAIT on I/O, indicating to the kernel to do not wait if request cannot be executed immediately. (see RWF_NOWAIT in preadv2(2))
-R, -rapid: Disk seek rate test, or bandwidth test if used together with -linear.
This option suppress human-readable output for each request (as -quiet), sets default interval to zero (-interval 0), stops measurement after 3 seconds (-work-time 3) and increases default working set size to 64m (-work-size 64m). Working set (-work-size) should be increased accordingly if disk has huge hardware cache.
-W, -write: Use writes rather than reads. Safe for temporary file in directory target. Write I/O gives more reliable results for systems where non-cached reads are not supported or cached at some level.

: Might be *DANGEROUS* for file/device: it will shred your data. In this case should be repeated three times (-WWW).

-G, -read-write: Alternate read and write requests.
-Y, -sync: Use sync I/O (see O_SYNC in open(2)).
-y, -dsync: Use data sync I/O (see O_DSYNC in open(2)).
-k, -keep: Keep and reuse temporary working file "ioping.tmp" (only for directory target).
-q, -quiet: Suppress periodical human-readable output.
-h, -help: Display help message and exit.
-v, -version: Display version and exit.

Argument suffixes

For options that expect time argument (-interval, -print-interval and -work-time), default is seconds, unless you specify one of the following suffixes (case-insensitive):

ns, nsec: nanoseconds (a billionth of a second, 1 / 1 000 000 000)
us, usec: microseconds (a millionth of a second, 1 / 1 000 000)
ms, msec: milliseconds (a thousandth of a second, 1 / 1 000)
s, sec: seconds
m, min: minutes
h, hour: hours

For options that expect "size" argument (-size, -speed-limit, -work-size and -work-offset), default is bytes, unless you specify one of the following suffixes (case-insensitive):

sector: disk sectors (a sector is always 512).
KiB, k, kb: kilobytes (1 024 bytes)
page: memory pages (a page is always 4KiB).
MiB, m, mb: megabytes (1 048 576 bytes)
GiB, g, gb: gigabytes (1 073 741 824 bytes)
TiB, t, tb: terabytes (1 099 511 627 776 bytes)

For options that expect "number" argument (-count and -print-count) you can optionally specify one of the following suffixes (case-insensitive):

k: kilo (thousands, 1 000)
m: mega (millions, 1 000 000)
g: giga (billions, 1 000 000 000)
t: tera (trillions, 1 000 000 000 000)

EXIT STATUS

Returns 0 upon success. The following error codes are defined:

1: Invalid usage (error in arguments).
2: Error during preparation stage.
3: Error during runtime.

RAW STATISTICS

ioping -print-count 100 -count 200 -interval 0 -quiet .
99 10970974 9024 36961531 90437 110818 358872 30756 100 12516420
100 9573265 10446 42785821 86849 95733 154609 10548 100 10649035
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)

(1) count of requests in statistics
(2) running time (nanoseconds)
(3) requests per second (iops)
(4) transfer speed (bytes per second)
(5) minimal request time (nanoseconds)
(6) average request time (nanoseconds)
(7) maximum request time (nanoseconds)
(8) request time standard deviation (nanoseconds)
(9) total requests (including warmup, too slow or too fast)
(10) total running time (nanoseconds)

JSON OUTPUT

With option -J|--json ioping prints json array of objects:
[
...
{
// timestamps
"timestamp": (unix time in seconds as float),
"localtime": (local time ISO 8601),

// io target
"target": {
"path": (target path),
"fstype": (filesystem name),
"device": (device name),
"device_size": (device size in bytes)
},

// io request
"io": {
"request": (request index),
"operation": (request type: "read" | "write"),
"size": (request size in bytes),
"time": (io time in ns),
"ignored": (ignored in statistics: true | false)
},

// statistics
"stat": {
"count": (nr reqeusts),
"size": (total io size in bytes),
"time": (total io time in ns),
"iops": (avg iops),
"bps": (avg rate),
"min": (min io time in ns),
"avg": (avg io time in ns),
"max": (max io time in ns),
"mdev": (standard deviation in ns)
},

// load statistics
"load": {
"count": (nr requests),
"size": (total io size in bytes),
"time": (total real time in ns),
"iops": (avg iops),
"bps": (avg rate)
},
},
...
]

EXAMPLES

ioping .: Show disk I/O latency using the default values and the current directory, until interrupted. This command prepares temporary (unlinked/hidden) working file and reads random chunks from it using non-cached read requests.
ioping -c 10 -s 1M /tmp: Measure latency on /tmp using 10 requests of 1 megabyte each.
ioping -R /dev/sda: Measure disk seek rate.
ioping -RL /dev/sda: Measure disk sequential speed.
ioping -RLB . | awk '{print $4}': Get disk sequential speed in bytes per second.
ioping -J . | jq -r --stream 'fromstream(1|truncate_stream(inputs)) | [.localtime, .io.time/1000000] | @tsv': Select localtime and io time in milliseconds from json outout.

HOMEPAGE

https://github.com/koct9i/ioping/.

AUTHORS

This program was written by Konstantin Khlebnikov koct9i@gmail.com.
Man-page was written by Kir Kolyshkin kir@openvz.org.