HP Serviceguard manual Choosing Cluster Lock Disks, Backing Up Cluster Lock Disk Information

The following is an example of mirroring the root logical volume:

lvextend -m 1 /dev/vg00/lvol3 /dev/dsk/c4t6d0

5.Update the boot information contained in the BDRA for the mirror copies of boot, root and primary swap.

/usr/sbin/lvlnboot -b /dev/vg00/lvol1 /usr/sbin/lvlnboot -s /dev/vg00/lvol2 /usr/sbin/lvlnboot -r /dev/vg00/lvol3

6.Verify that the mirrors were properly created. lvlnboot -v

The output of this command is shown in a display like the following:

Boot Definitions for Volume Group /dev/vg00:

Physical Volumes belonging in Root Volume Group:

	/dev/dsk/c4t5d0		(10/0.5.0) -- Boot Disk
	/dev/dsk/c4t6d0		(10/0.6.0) -- Boot Disk
Boot:	lvol1	on:	/dev/dsk/c4t5d0
			/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. See “Cluster Lock ” (page 46) and “Cluster Lock Planning” (page 98) for discussion of cluster lock options.

The cluster lock disk is configured on an LVM 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 I/O timeout values are used for the cluster lock physical volumes. Changing the I/O 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 I/O 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.” For instructions on setting up a lock disk, see “Specifying a Lock Disk” (page 188).

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.

Preparing Your Systems 173