Goal of PowerHA SystemMirror: Eliminating scheduled downtime

The primary goal of high availability clustering software is to minimize, or ideally, eliminate, the need to take your resources out of service during maintenance and reconfiguration activities.

PowerHA® SystemMirror® software optimizes availability by allowing for the dynamic reconfiguration of running clusters. Most routine cluster maintenance tasks, such as adding or removing a node or changing the priority of nodes participating in a resource group, can be applied to an active cluster without stopping and restarting cluster services. In addition, you can keep a PowerHA SystemMirror cluster online while making configuration changes by using the Cluster Single Point of Control (C-SPOC) facility. C-SPOC makes cluster management easier because you can change to shared volume groups, users, and groups across the cluster from a single node. The changes are propagated transparently to other cluster nodes.