Managing Serviceguard 12th Edition, March 2006

Building an HA Cluster Configuration
Preparing Your Systems
Chapter 5 205
Preparing for Changes in Cluster Size
If you intend to add additional nodes to the cluster online, while it is
running, ensure that they are connected to the same heartbeat subnets
and to the same lock disks as the other cluster nodes. In selecting a
cluster lock configuration, be careful to anticipate any potential need for
additional cluster nodes. Remember that a cluster of more than four
nodes may not use a lock disk, but a two-node cluster must use a cluster
lock. Thus, if you will eventually need five nodes, you should build an
initial configuration that uses a quorum server.
If you intend to remove a node from the cluster configuration while the
cluster is running, ensure that the resulting cluster configuration will
still conform to the rules for cluster locks described above.
If you are planning to add a node online, and a package will run on the
new node, ensure that any existing cluster bound volume groups for the
package have been imported to the new node. Also, ensure that the
MAX_CONFIGURED_PACKAGES parameter is set high enough to
accommodate the total number of packages you will be using.