HP Serviceguard Extension for RAC (SGeRAC) manual Activating an LVM Volume Group in Shared Mode

#vgchange -S y -c y /dev/vg_rac

This command is issued from the configuration node only, and the cluster must be running on all nodes for the command to succeed. Note that both the -Sand the -coptions are specified. The -S y option makes the volume group shareable, and the -c y option causes the cluster ID to be written out to all the disks in the volume group. This command specifies the cluster that a node must be a part of to obtain shared access to the volume group.

Making a Volume Group Unshareable

Use the following steps to unmark a previously marked shared volume group:

1.Remove the volume group name from the ASCII cluster configuration file.

2.Enter the following command:

# vgchange -S n -c n /dev/volumegroup

The above example marks the volume group as non-shared, and not associated with a cluster.

Activating an LVM Volume Group in Shared Mode

Activation and deactivation of shared volume groups is normally done through a control script. If you need to perform activation from the command line, you can issue the following command from each node to activate the volume group in shared mode. (The node where you first enter the command becomes the server node.)

#vgchange -a s -p /dev/vg_rac

The following message is displayed:

Activated volume group in shared mode.

This node is the Server.

When the same command is entered on the second node, the following message is displayed:

Activated volume group in shared mode.

This node is a Client.

NOTE: Do not share volume groups that are not part of the RAC configuration unless shared access is controlled.

Deactivating a Shared Volume Group

Issue the following command from each node to deactivate the shared volume group:

#vgchange -a n /dev/vg_rac

Remember that volume groups remain shareable even when nodes enter and leave the cluster.

NOTE: If you wish to change the capacity of a volume group at a later time, you must deactivate and unshare the volume group first. If you add disks, you must specify the appropriate physical volume group name and make sure the /etc/lvmpvg file is correctly updated on both nodes.

Making Offline Changes to Shared Volume Groups

You may need to change the volume group configuration of RAC shared logical volumes to add capacity to the data files or to add log files. No configuration changes are allowed on shared LVM volume groups while they are activated. The volume group must be deactivated first on all nodes, and marked as non-shareable.

To learn more about an additional method, Single Node Online volume Re-Configuration (SNOR), please see the white paper SLVM Online Volume Re-configurationat www.hp.com/go/ hpux-core-docs —> HP-UX 11i v3 —> White papers.

Use the following procedure (examples assume the volume group is being shared by node 1 and node 2, and they use the volume group vg_rac):

128 Maintenance