cmdisklock(1m)															    cmdisklock(1m)

NAME

       cmdisklock - manage Serviceguard cluster lock devices.

SYNOPSIS

       cmdisklock check path
       cmdisklock [-f] reset path

DESCRIPTION

       cmdisklock is a tool to check the current state of a Serviceguard cluster lock device.  It can also be used to reset the state of the clus-
       ter lock device.  The need to reset the cluster lock device state could arise if the cluster lock device is replaced or becomes corrupt.

       A cluster lock device can be either an HP-UX LVM cluster lock or a cluster lock LUN device.  HP-UX LVM cluster locks exist only on  a  disk
       in an LVM volume group.	Cluster lock LUNs exist only on disks dedicated to cluster lock.  cmdisklock is useful for checking either type of
       cluster lock and for re-initializing cluster lock LUN devices after a failure or corruption.

       NOTE
       To restore an HP-UX LVM cluster lock, use vgcfgrestore.	cmdisklock will fail until vgcfgrestore is run, and cmdisklock is  unnecessary	as
       long as vgcfgbackup was done after the cluster lock was initialized.  See the Managing Serviceguard manual for details.

       The  syntax  of	the  path  option  depends  on	the  type  of  lock.  For  HP-UX LVM cluster lock disks, the syntax is VG:PV (for example:
       /dev/vglock:/dev/dsk/c0t0d2).  For cluster lock LUN disks, the path is the  disk  device  path.	 For  example,	/dev/sdd1  (on	Linux)	or
       /dev/dsk/c0t1d2 (on HP-UX).

   Options
       cmdisklock supports the following options:

	      check	       Check the current state of the cluster lock device and report the results.

	      reset	       Reset (initialize) the state of the cluster lock device.  This operation should only be performed on a cluster lock
			       LUN device.  For HP-UX LVM cluster lock, use vgcfgrestore as documented in the Managing Serviceguard manual.  After
			       performing a reset, a check can be used to verify that the lock is cleared.

EXAMPLES

       If the cluster lock LUN device becomes corrupted and the cluster is up, messages like the following will appear in syslog.

       Mar  15	12:20:41  usb  cmdisklockd[17599]:  WARNING: Cluster lock LUN /dev/dsk/c0t1d2 is corrupt: bad label.  Until this situation is cor-
       rected, a single failure could cause all nodes in the cluster to crash.
       Mar 15 12:20:41 usb cmdisklockd[17599]: After ensuring that all active nodes in the cluster have logged this message, run 'cmdisklock reset
       /dev/dsk/c0t1d2' to repair
       Mar 15 12:20:41 usb cmdisklockd[17599]: Cluster lock disk /dev/dsk/c0t1d2 is inaccessible

       Once the above messages appear in syslog on all running nodes, the following command will re-initialize the cluster lock LUN:

       ucd:/> cmdisklock reset /dev/dsk/c0t1d2
       WARNING: Cluster lock LUN /dev/dsk/c0t1d2 is corrupt: bad label.  Until this situation is corrected, a single failure could cause all nodes
       in the cluster to crash.
       After ensuring that all active nodes in the cluster have logged this message, run 'cmdisklock reset /dev/dsk/c0t1d2' to repair
       /dev/dsk/c0t1d2 is inaccessible
       Resetting cluster lock device /dev/dsk/c0t1d2
       Cluster lock reset completed
       /dev/dsk/c0t1d2 is accessible
       cleared

       After the lock is restored, a message like the following appears in syslog:

       Mar 15 12:23:11 usb cmdisklockd[17599]: Cluster lock disk /dev/dsk/c0t1d2 is accessible

WARNINGS

       CAUTION
       For cluster lock LUN, reset is a potentially destructive operation.  While cmdisklock checks for known volume manager and file  system  use
       (overridden  by	-f),  it does not validate that the device to be reset is actually used by any cluster.  If -f is used on the wrong device
       file, loss of data may result.

       CAUTION
       Care should be taken when doing a reset when the cluster is active as there is a remote possibility that the cluster will  partition  right
       when this command is run and both nodes could end up thinking they have successfully acquired the lock.	To avoid this situation, make sure
       cmcld has logged a message in syslog on all running nodes saying the device is inaccessble, before performing a reset.	Note  that  it	is
       safe to run cmdisklock when the cluster is down.

RETURN VALUE

       cmdisklock returns the following values:

	      0    Successful completion.
	      1    The disk is inaccessible or is not recognized as a cluster lock.

AUTHOR

       cmdisklock was developed by HP.

SEE ALSO

       cmapplyconf(1m), cmviewcl(1m), vgcfgbackup(1m), vgcfgrestore(1m)

						      Requires Optional Serviceguard Software					    cmdisklock(1m)