Managing Serviceguard 11th Edition, Version A.11.16, Second Printing June 2004

Serviceguard at a Glance
What is Serviceguard?
Chapter 1 25
node which are central to the operation of the cluster. TCP/IP services
also are used for other types of inter-node communication. (The
heartbeat is explained in more detail in the chapter “Understanding
Serviceguard Software.”)
Failover
Under normal conditions, a fully operating Serviceguard cluster simply
monitors the health of the cluster's components while the packages are
running on individual nodes. Any host system running in the
Serviceguard cluster is called an active node. When you create the
package, you specify a primary node and one or more adoptive nodes.
When a node or its network communications fails, Serviceguard can
transfer control of the package to the next available adoptive node. This
situation is shown in Figure 1-2.
Figure 1-2 Typical Cluster After Failover