Managing Serviceguard 12th Edition, March 2006

Building an HA Cluster Configuration
Preparing Your Systems
Chapter 5202
/dev/dsk/c4t6d0
Root: lvol3 on: /dev/dsk/c4t5d0
/dev/dsk/c4t6d0
Swap: lvol2 on: /dev/dsk/c4t5d0
/dev/dsk/c4t6d0
Dump: lvol2 on: /dev/dsk/c4t6d0, 0
Choosing Cluster Lock Disks
The following guidelines apply if you are using a lock disk. The cluster
lock disk is configured on a volume group that is physically connected to
all cluster nodes. This volume group may also contain data that is used
by packages.
When you are using dual cluster lock disks, it is required that the default
IO timeout values are used for the cluster lock physical volumes.
Changing the IO timeout values for the cluster lock physical volumes can
prevent the nodes in the cluster from detecting a failed lock disk within
the allotted time period which can prevent cluster re-formations from
succeeding. To view the existing IO timeout value, run the following
command:
# pvdisplay <lock device file name>
The IO Timeout value should be displayed as “default.” To set the IO
Timeout back to the default value, run the command:
# pvchange -t 0 <lock device file name>
The use of a dual cluster lock is only allowed with certain specific
configurations of hardware. Refer to the discussion in Chapter 3 on
“Dual Cluster Lock.”
Backing Up Cluster Lock Disk Information
After you configure the cluster and create the cluster lock volume group
and physical volume, you should create a backup of the volume group
configuration data on each lock volume group. Use the vgcfgbackup
command for each lock volume group you have configured, and save the
backup file in case the lock configuration must be restored to a new disk
with the vgcfgrestore command following a disk failure.