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.
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:
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 pcp.conf(5).
For environment variables affecting PCP tools, see pmGetOptions(3).
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
2020-08-13. (At that time, the date of the most recent commit that
was found in the repository was 2020-08-11.) 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)