clvmd(8)

1CLVMD(8)                    System Manager's Manual                   CLVMD(8)
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NAME

6       clvmd — cluster LVM daemon
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SYNOPSIS

9       clvmd [-C] [-d [value]] [-E lock_uuid] [-f] [-h] [-I cluster_manager]
10       [-R] [-S] [-t timeout] [-T start_timeout] [-V]
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DESCRIPTION

13       clvmd is the daemon that distributes  LVM  metadata  updates  around  a
14       cluster.   It must be running on all nodes in the cluster and will give
15       an error if a node in the cluster does not have this daemon running.
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17       Also see lvmlockd(8) for a newer method of using LVM on shared storage.
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OPTIONS

20       -C
21              Only valid if -d is also specified.  Tells all clvmds in a clus‐
22              ter  to enable/disable debug logging.  Without this switch, only
23              the local clvmd will change its debug level to that  given  with
24              -d.
25              This  does  not  work correctly if specified on the command-line
26              that starts clvmd.  If you want to start clvmd and enable  clus‐
27              ter-wide logging then the command needs to be issued twice, eg:
28              clvmd
29              clvmd -d2
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31       -d [value]
32              Set  debug  logging  level.   If -d is specified without a value
33              then 1 is assumed. Value can be:
34              0 — Disabled
35              1 — Sends debug logs to stderr (implies -f)
36              2 — Sends debug logs to syslog(3)
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38       -E lock_uuid
39              Pass lock uuid  to  be  reacquired  exclusively  when  clvmd  is
40              restarted.
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42       -f
43              Don't fork, run in the foreground.
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45       -h
46              Show help information.
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48       -I cluster_manager
49              Selects the cluster manager to use for locking and internal com‐
50              munications. As it is quite possible to have  multiple  managers
51              available  on the same system you might have to manually specify
52              this option to override the search.
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54              By default, omit -I is equivalent to -Iauto.  Clvmd will use the
55              first  cluster  manager  that  succeeds, and it checks them in a
56              predefined order cman, corosync, openais.   The  available  man‐
57              agers will be listed by order as part of the clvmd -h output.
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59       -R
60              Tells all the running instance of clvmd in the cluster to reload
61              their device  cache  and  re-read  the  lvm  configuration  file
62              lvm.conf(5).  This command should be run whenever the devices on
63              a cluster system are changed.
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65       -S
66              Tells the running clvmd to exit and reexecute itself, for  exam‐
67              ple  at  the  end  of  a  package  upgrade.  The new instance is
68              instructed to reacquire any locks in the same state as they were
69              previously  held.  (Alternative methods of restarting the daemon
70              have the side effect of changing exclusive LV locks into  shared
71              locks.)
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73       -t timeout
74              Specifies  the  timeout  for commands to run around the cluster.
75              This should not be so small that commands with many disk updates
76              to  do  will  fail,  so you may need to increase this on systems
77              with very large disk farms.  The default is 60 seconds.
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79       -T start_timeout
80              Specifies the start timeout for clvmd  daemon  startup.  If  the
81              daemon  does  not report that it has started up within this time
82              then the parent command will exit with status of  5.  This  does
83              NOT  mean  that clvmd has not started! What it means is that the
84              startup has been delayed for some reason; the most likely  cause
85              of  this is an inquorate cluster though it could be due to lock‐
86              ing latencies on a cluster with large numbers  of  logical  vol‐
87              umes.  If  you get the return code of 5 it is usually not neces‐
88              sary to restart clvmd it will start as soon as that blockage has
89              cleared.   This  flag  is  to allow startup scripts to exit in a
90              timely fashion even if the cluster is stalled for some reason.
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92              The default is 0 (no timeout) and the value is in seconds. Don't
93              set this too small or you will experience spurious errors. 10 or
94              20 seconds might be sensible.
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96              This timeout will be ignored if you start clvmd with the -d.
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98       -V
99              Display the version of the cluster LVM daemon.
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NOTES

102   Activation
103       In a clustered VG, clvmd is used for activation, and the following val‐
104       ues are possible with lvchange/vgchange -a:
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106       y|sy   clvmd  activates  the  LV  in  shared mode (with a shared lock),
107              allowing multiple nodes to activate the LV concurrently.  If the
108              LV  type prohibits shared access, such as an LV with a snapshot,
109              an exclusive lock is automatically used instead.  clvmd attempts
110              to activate the LV concurrently on all nodes.
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112       ey     clvmd  activates  the  LV  in  exclusive mode (with an exclusive
113              lock), allowing  a  single  node  to  activate  the  LV.   clvmd
114              attempts  to activate the LV concurrently on all nodes, but only
115              one will succeed.
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117       ly     clvmd attempts to activate the LV only on the  local  node.   If
118              the  LV type allows concurrent access, then shared mode is used,
119              otherwise exclusive.
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121       n      clvmd attempts to deactivate the LV on all nodes.
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123       ln     clvmd attempts to deactivate the LV on the local node.
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ENVIRONMENT VARIABLES

126       LVM_CLVMD_BINARY
127              The CLVMD  binary  to  use  when  clvmd  restart  is  requested.
128              Defaults to /usr/clvmd.
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130       LVM_BINARY
131              The LVM2 binary to use.  Defaults to /usr/lvm.
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FILES

134       /usr/clvmd
135       /usr/lvm
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