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)