NAME

       clvmd — cluster LVM daemon

SYNOPSIS

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

DESCRIPTION

       clvmd is the daemon that distributes LVM metadata updates around a cluster.   It  must  be
       running  on  all nodes in the cluster and will give an error if a node in the cluster does
       not have this daemon running.

       Also see lvmlockd(8) for a newer method of using LVM on shared storage.

OPTIONS

       -C
              Only  valid  if  -d  is  also  specified.   Tells  all  clvmds  in  a  cluster   to
              enable/disable  debug  logging.   Without  this  switch,  only the local clvmd will
              change its debug level to that given with -d.
              This does not work correctly if specified on the command-line  that  starts  clvmd.
              If  you  want to start clvmd and enable cluster-wide logging then the command needs
              to be issued twice, eg:
              clvmd
              clvmd -d2

       -d [value]
              Set debug logging level.  If -d is specified without a value  then  1  is  assumed.
              Value can be:
              0 — Disabled
              1 — Sends debug logs to stderr (implies -f)
              2 — Sends debug logs to syslog(3)

       -E lock_uuid
              Pass lock uuid to be reacquired exclusively when clvmd is restarted.

       -f
              Don't fork, run in the foreground.

       -h
              Show help information.

       -I cluster_manager
              Selects  the  cluster manager to use for locking and internal communications. As it
              is quite possible to have multiple managers available on the same system you  might
              have to manually specify this option to override the search.

              By  default,  omit  -I  is  equivalent to -Iauto.  Clvmd will use the first cluster
              manager that succeeds, and it checks them in a  predefined  order  cman,  corosync,
              openais.   The  available  managers will be listed by order as part of the clvmd -h
              output.

       -R
              Tells all the running instance of clvmd in the cluster to reload their device cache
              and  re-read  the  lvm  configuration  file lvm.conf(5). This command should be run
              whenever the devices on a cluster system are changed.

       -S
              Tells the running clvmd to exit and reexecute itself, for example at the end  of  a
              package  upgrade. The new instance is instructed to reacquire any locks in the same
              state as they were previously held. (Alternative methods of restarting  the  daemon
              have the side effect of changing exclusive LV locks into shared locks.)

       -t timeout
              Specifies the timeout for commands to run around the cluster. This should not be so
              small that commands with many disk updates to do will fail,  so  you  may  need  to
              increase this on systems with very large disk farms.  The default is 60 seconds.

       -T start_timeout
              Specifies the start timeout for clvmd daemon startup. If the daemon does not report
              that it has started up within this time then the  parent  command  will  exit  with
              status  of  5. This does NOT mean that clvmd has not started! What it means is that
              the startup has been delayed for some reason; the most likely cause of this  is  an
              inquorate  cluster  though  it  could be due to locking latencies on a cluster with
              large numbers of logical volumes. If you get the return code of 5 it is usually not
              necessary  to  restart  clvmd  it  will start as soon as that blockage has cleared.
              This flag is to allow startup scripts to exit in  a  timely  fashion  even  if  the
              cluster is stalled for some reason.

              The default is 0 (no timeout) and the value is in seconds. Don't set this too small
              or you will experience spurious errors. 10 or 20 seconds might be sensible.

              This timeout will be ignored if you start clvmd with the -d.

       -V
              Display the version of the cluster LVM daemon.

NOTES

   Activation
       In a clustered VG, clvmd is used for activation, and the  following  values  are  possible
       with lvchange/vgchange -a:

       y|sy   clvmd activates the LV in shared mode (with a shared lock), allowing multiple nodes
              to activate the LV concurrently.  If the LV type prohibits shared access,  such  as
              an  LV  with  a  snapshot,  an exclusive lock is automatically used instead.  clvmd
              attempts to activate the LV concurrently on all nodes.

       ey     clvmd activates the LV in exclusive mode  (with  an  exclusive  lock),  allowing  a
              single  node to activate the LV.  clvmd attempts to activate the LV concurrently on
              all nodes, but only one will succeed.

       ly     clvmd attempts to activate the LV only on the local node.  If the  LV  type  allows
              concurrent access, then shared mode is used, otherwise exclusive.

       n      clvmd attempts to deactivate the LV on all nodes.

       ln     clvmd attempts to deactivate the LV on the local node.

ENVIRONMENT VARIABLES

       LVM_CLVMD_BINARY
              The CLVMD binary to use when clvmd restart is requested.  Defaults to /clvmd.

       LVM_BINARY
              The LVM2 binary to use.  Defaults to /lvm.

FILES

       /clvmd
       /lvm

SEE ALSO

       syslog(3), lvm.conf(5), lvm(8), lvmlockd(8), lvmsystemid(7)