Managing HP Serviceguard A.11.20.10 for Linux, December 2012

Power Supply Enter the power supply unit number of the UPS to which the host or other

device is connected.

Be sure to follow UPS, power circuit, and cabinet power limits as well as SPU power limits.

4.4.1 Power Supply Configuration Worksheet

The Power Supply Planning worksheet (page 273) will help you organize and record your specific

power supply configuration. Make as many copies as you need.

4.5 Cluster Lock Planning

The purpose of the cluster lock is to ensure that only one new cluster is formed in the event that

exactly half of the previously clustered nodes try to form a new cluster. It is critical that only one

new cluster is formed and that it alone has access to the disks specified in its packages. You can

specify a lock LUN or a quorum server as the cluster lock. For more information about the cluster

lock, see“Cluster Lock” (page 38).

NOTE: You cannot use more than one type of lock in the same cluster.

4.5.1 Cluster Lock Requirements

A one-node cluster does not require a lock. Two-node clusters require the use of a cluster lock, and

a lock is recommended for larger clusters as well. Clusters larger than four nodes can use only a

quorum server as the cluster lock.

For information on configuring lock LUNs and the Quorum Server, see “Setting up a Lock LUN”

(page 137), section “Specifying a Lock LUN” (page 149), and HP Serviceguard Quorum Server

Version A.04.00, or later Release Notes at http://www.hp.com/go/hpux-serviceguard-docs (Select

HP Serviceguard Quorum Server Software).

4.5.2 Planning for Expansion

Bear in mind that a cluster with more than 4 nodes cannot use a lock LUN. So if you plan to add

enough nodes to bring the total to more than 4, you should use a quorum server.

4.5.3 Using a Quorum Server

The Quorum Server is described under “Use of the Quorum Server as a Cluster Lock” (page 39).