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

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

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

DESCRIPTION
       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 device.

       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
       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 are:

       -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.

PCP ENVIRONMENT
       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 pcp.conf(5).

       For environment variables affecting PCP tools, see pmGetOptions(3).

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

Performance Co-Pilot                  PCP                       PCP-DMCACHE(1)