Managing Serviceguard Fifteenth Edition, reprinted May 2008

Planning and Documenting an HA Cluster
Cluster Lock Planning
Chapter 4146
Planning for Expansion
Bear in mind that a cluster with more than 4 nodes cannot use a lock
disk or lock LUN. Thus, if you plan to add enough nodes to bring the total
to more than 4, you should use a quorum server.
Using a Quorum Server
The operation of Quorum Server is described under “Use of the Quorum
Server as the Cluster Lock” on page 72. See also “Cluster Lock” on
page 68.
A quorum server:
• Can be used with up to 150 clusters, not exceeding 300 nodes total.
• Can support a cluster with any supported number of nodes.
• Must be configured on an IPv4, not an IPv6, network.
• Can communicate with the cluster on up to two subnets (a primary
and an alternate).
IMPORTANT If you plan to use a Quorum Server, make sure you read the HP
Serviceguard Quorum Server Version A.03.00 Release Notes before you
proceed. You can find them at: http://www.docs.hp.com -> High
Availability -> Quorum Server. You should also consult the Quorum
Server white papers at the same location.