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

6       pcp-dmcache, pcp-lvmcache - report on logical storage device caches
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SYNOPSIS

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

12       pcp-dmcache  reports  on  the  activity of any configured Device Mapper
13       Cache targets.  The reported information includes  device  IOPs,  cache
14       and  metadata  device  utilization,  as  well as hit and miss rates and
15       ratios for both reads and writes for each cache device.
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17       pcp-lvmcache (Logical Volume Manager cache) is  an  exact  synonym  for
18       pcp-dmcache (Device Mapper cache).
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20       By  default,  pcp-dmcache reports on all available cache target devices
21       (one line each, per sample), but this can  be  restricted  to  specific
22       devices on the command line.
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OPTIONS

25       When  invoked  via  the  pcp(1)  command,  the -h/--host, -a/--archive,
26       -O/--origin, -s/--samples,  -t/--interval,  -Z/--timezone  and  several
27       other pcp options become indirectly available.
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29       Additional  options  are available for changing the output displayed by
30       pcp-dmcache.
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32       -i, --iops
33              displays total read and write operations instead of the  default
34              cache hit ratio.
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36       -R, --repeat
37              changes  the frequency at which the column heading is displayed.
38              By default, a header is displayed after every tenth sample.
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40       -V, --version
41              Display version number and exit.
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43       -?, --help
44              Display usage message and exit.
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PCP ENVIRONMENT

47       Environment variables with the prefix PCP_ are used to parameterize the
48       file  and  directory names used by PCP.  On each installation, the file
49       /etc/pcp.conf contains the  local  values  for  these  variables.   The
50       $PCP_CONF  variable may be used to specify an alternative configuration
51       file, as described in pcp.conf(5).
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53       For environment variables affecting PCP tools, see pmGetOptions(3).
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SEE ALSO

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