Managing Serviceguard Eighteenth Edition, September 2010

NOTE: If you restore or recreate the volume group for the lock disk and you need to
re-create the cluster lock (for example if no vgcfgbackup is available), you can run
cmdisklock to re-create the lock. See the cmdisklock (1m) manpage for more
information.
Replacing a Lock LUN
You can replace an unusable lock disk while the cluster is running. You can do this
without any cluster reconfiguration if you do not change the devicefile name (Device
Special File, or DSF); or, if you need to change the DSF, you can do the necessary
reconfiguration while the cluster is running.
IMPORTANT: If you need to replace a LUN under the HP-UX 11i v3 agile addressing
scheme, also used by cDSFs (see “About Device File Names (Device Special Files)”
(page 106) and “About Cluster-wide Device Special Files (cDSFs)” (page 135), and you
use the same DSF, you may need to use the io_redirect_dsf(1M) command to
reassign the existing DSF to the new device, depending on whether the operation
changes the WWID of the LUN; see the section on io_redirect_dsf in the white
paper The Next Generation Mass Storage Stack at www.hp.com/go/hpux-core-docs.
If you are not able to use the existing DSF for the new device, or you decide not to, you
must change the name of the DSF in the cluster configuration file and re-apply the
configuration; see “Updating the Cluster Lock LUN Configuration Online” (page 364).
Do this after running vgcfgrestore as described below.
CAUTION: Before you start, make sure that all nodes have logged a message such as
the following in syslog:
WARNING: Cluster lock LUN /dev/dsk/c0t1d1 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/dsk/c0t1d1
Replacing Disks 405