BLKIOMON(8)                                                      BLKIOMON(8)

NAME         top

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

SYNOPSIS         top

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

DESCRIPTION         top

       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.

OPTIONS         top

       -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.

EXAMPLES         top

       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 -

AUTHORS         top

       blkiomon and this man page were written by Martin Peschke.

REPORTING BUGS         top

       Report bugs to <>

COPYRIGHT         top

       Copyright © 2008 IBM Corp.
       This is free software.  You may redistribute copies of it under the
       terms of the GNU General Public License
       <>.  There is NO WARRANTY, to the
       extent permitted by law.

SEE ALSO         top

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

COLOPHON         top

       This page is part of the blktrace (Linux block layer I/O tracer)
       project.  Information about the project can be found at [unknown --
       if you know, please contact] It is not known how
       to report bugs for this man page; if you know, please send a mail to  This page was obtained from the project's
       upstream Git repository
       ⟨⟩ on
       2018-10-29.  (At that time, the date of the most recent commit that
       was found in the repository was 2018-08-31.)  If you discover any
       rendering problems in this HTML version of the page, or you believe
       there is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to

                                July 17, 2008                    BLKIOMON(8)