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.
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
displays total read and write operations instead of the
default cache hit ratio.
changes the frequency at which the column heading is
displayed. By default, a header is displayed after every
Display version number and exit.
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
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 email@example.com. This page was obtained from the
project's upstream Git repository
⟨https://github.com/performancecopilot/pcp.git⟩ on 2021-08-27.
(At that time, the date of the most recent commit that was found
in the repository was 2021-08-27.) 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
Performance Co-Pilot PCP PCP-DMCACHE(1)