blkiomon man page

blkiomon — monitor block device I/O based o blktrace data


blkiomon -I interval [ -h file ] [ -b file ] [ -d file ] [ -D file ] [ -Q path_name -q msg_queue_id -m msg_id ] [ -V ]


blkiomon is a block device I/O monitor. It periodically generates per-device request size and request latency statistics from blktrace data. It provides histograms as well as data that can be used to calculate min, max, average and variance. For this purpose, it consumes D and C traces read from stdin. Note, that this doesn't work for logical volumes, as high-level drivers don't see the completion of the events (C).

There are options for binary output and human-readable output to files and stdout. Output to a message queue is supported as well.

There is no need to use blkparse with blkiomon. blkiomon is capable of consuming binary output written to stdout by blktrace.


-I interval
Set sample interval
-h file
Human-readable output file. Use '-' for stdout.
-b file
Binary output file. Use '-' for stdout.
-d file
Output file for data emitted by low level device driver.
-D file
Output file for debugging data. Use '-' for stdout.
-Q path_name
Sets path_name as path name for existing message queue to be used for binary output.
-q msg_queue_id
Sets msg_queue_id as ID for an existing message queue to be used for binary output.
-m msg_id
Sets msg_id as message identifier to be used for binary output messages written to an existing message queue.
Print program version.


To get I/O statistics for /dev/sdw every 10 seconds for a period of one hour, use the following command:

% blktrace /dev/sdw -a issue -a complete -w 3600 -o - | blkiomon -I 10 -h -


blkiomon and this man page were written by Martin Peschke.

Reporting Bugs

Report bugs to <>

See Also

btrace (8), blktrace (8), blkparse (1), verify_blkparse (1), blkrawverify (1), btt (1)


July 17, 2008