A clustered pair topology is two or more pairs of Solaris hosts that operate under a single cluster administrative framework. In this configuration, failover occurs only between a pair. However, all hosts 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. More than two hosts can run a scalable service or parallel database, even though all the hosts are not directly connected to the disks that store the application data.
The following figure illustrates a clustered pair configuration.