pcp-dmcache(1) — Linux manual page


PCP-DMCACHE(1)           General Commands Manual          PCP-DMCACHE(1)

NAME         top

       pcp-dmcache, pcp-lvmcache - report on logical storage device

SYNOPSIS         top

       pcp [pcp options] dmcache [-iRV?] [device ...]

DESCRIPTION         top

       pcp-dmcache reports on the activity of any configured Device
       Mapper Cache targets.  The reported information includes device
       IOPs, cache and metadata device utilization, as well as hit and
       miss rates and ratios for both reads and writes for each cache

       pcp-lvmcache (Logical Volume Manager cache) is an exact synonym
       for pcp-dmcache (Device Mapper cache).

       By default, pcp-dmcache reports on all available cache target
       devices (one line each, per sample), but this can be restricted
       to specific devices on the command line.

OPTIONS         top

       When invoked via the pcp(1) command, the -h/--host, -a/--archive,
       -O/--origin, -s/--samples, -t/--interval, -Z/--timezone and
       several other pcp options become indirectly available; refer to
       PCPIntro(1) for a complete description of these options.

       The additional command line options available for pcp-dmcache

       -i, --iops
              displays total read and write operations instead of the
              default cache hit ratio.

       -R, --repeat
              changes the frequency at which the column heading is
              displayed.  By default, a header is displayed after every
              tenth sample.

       -V, --version
              Display version number and exit.

       -?, --help
              Display usage message and exit.


       Environment variables with the prefix PCP_ are used to
       parameterize the file and directory names used by PCP.  On each
       installation, the file /etc/pcp.conf contains the local values
       for these variables.  The $PCP_CONF variable may be used to
       specify an alternative configuration file, as described in

       For environment variables affecting PCP tools, see

SEE ALSO         top

       PCPIntro(1), pcp(1), pmdadm(1), dmsetup(1) and lvmcache(7).

COLOPHON         top

       This page is part of the PCP (Performance Co-Pilot) project.
       Information about the project can be found at 
       ⟨http://www.pcp.io/⟩.  If you have a bug report for this manual
       page, send it to pcp@groups.io.  This page was obtained from the
       project's upstream Git repository
       ⟨https://github.com/performancecopilot/pcp.git⟩ on 2023-12-22.
       (At that time, the date of the most recent commit that was found
       in the repository was 2023-12-16.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there
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       (which is not part of the original manual page), send a mail to

Performance Co-Pilot               PCP                    PCP-DMCACHE(1)