Managing HP Serviceguard for Linux Ninth Edition, April 2009

If you need to use a different devicefile, you must change the name of the devicefile in
the cluster configuration file; see “Updating the Cluster Lock LUN Configuration
Online” (page 251).
CAUTION: Before you start, make sure that all nodes have logged a message such as
the following in syslog:
WARNING: Cluster lock LUN /dev/sda1 is corrupt: bad label. Until
this situation is corrected, a single failure could cause all
nodes in the cluster to crash.
Once all nodes have logged this message, use a command such as the following to
specify the new cluster lock LUN:
cmdisklock reset /dev/sda1
CAUTION: You are responsible for determining that the device is not being used by
LVM or any other subsystem on any node connected to the device before using
cmdisklock. If you use cmdisklock without taking this precaution, you could lose
data.
NOTE: cmdisklock is needed only when you are repairing or replacing a lock LUN;
see the cmdisklock (1m) manpage for more information.
Serviceguard checks the lock LUN every 75 seconds. After using the cmdisklock
command, review the syslog file of an active cluster node for not more than 75 seconds.
By this time you should see a message showing that the lock disk is healthy again.
Revoking Persistent Reservations after a Catastrophic Failure
For information about persistent reservations (PR) and how they work, see “About
Persistent Reservations” (page 85).
Under normal circumstances, Serviceguard clears all persistent reservations when a
package halts. In the case of a catastrophic cluster failure however, you may need to
do the cleanup yourself as part of the recovery. Use the
$SGCONF/scripts/sg/pr_cleanup script to do this. (The script is also in
$SGCONF/bin/. See “Understanding the Location of Serviceguard Files” (page 147)
for the locations of Serviceguard directories on various Linux distributions.)
Invoke the script as follows, specifying either the device special file (DSF) of a LUN,
or a file containing a list of DSF names:
274 Troubleshooting Your Cluster