1PCP-DMCACHE(1)              General Commands Manual             PCP-DMCACHE(1)
2
3
4

NAME

6       pcp-dmcache, pcp-lvmcache - report on logical storage device caches
7

SYNOPSIS

9       pcp [pcp options] dmcache [-i/--iops] [-R/--repeat N] [device ...]
10

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.
16
17       pcp-lvmcache (Logical Volume Manager cache) is  an  exact  synonym  for
18       pcp-dmcache (Device Mapper cache).
19
20       When  invoked  via  the  pcp(1)  command,  the -h/--host, -a/--archive,
21       -O/--origin, -s/--samples,  -t/--interval,  -Z/--timezone  and  several
22       other pcp options become indirectly available.
23
24       By  default,  pcp-dmcache reports on all available cache target devices
25       (one line each, per sample), but this can  be  restricted  to  specific
26       devices on the command line.
27

OPTIONS

29       Additional  options  are available for changing the output displayed by
30       pcp-dmcache.
31
32       -i/--iops displays total read  and  write  operations  instead  of  the
33       default cache hit ratio.
34
35       -R/--repeat  changes  the frequency at which the column heading is dis‐
36       played.  By default, a header is displayed after every tenth sample.
37

SEE ALSO

39       pcp(1), pmdadm(1), dmsetup(1), PCPIntro(1) and lvmcache(7).
40
41
42
43Performance Co-Pilot                  PCP                       PCP-DMCACHE(1)
Impressum