A clustered pairs topology is two or more pairs of nodes operating under a single cluster administrative framework. In this configuration, failover occurs only between a pair. However, all nodes are connected by the cluster interconnect and operate under Sun Cluster software control. You might use this topology to run a parallel database application on one pair and a failover or scalable application on another pair.
Using the cluster file system, you could also have a two-pair configuration where more than two nodes run a scalable service or parallel database even though all of the nodes are not directly connected to the disks that store the application data.
The following figure illustrates a clustered pair configuration.