Identifying and keeping available your cluster resources

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The PowerHA® SystemMirror® software provides a highly available environment.

The PowerHA SystemMirror software does this by:

  • Identifying the set of cluster resources that are essential to the operation of an application, and combining those resources into a resource group.
  • Defining the resource group policies and attributes that dictate how PowerHA SystemMirror manages resources to keep them highly available at different stages of cluster operation (startup, fallover and fallback).

By identifying resources and defining resource group policies, the PowerHA SystemMirror software makes numerous cluster configurations possible, providing tremendous flexibility in defining a cluster environment tailored to individual requirements.

Identifying cluster resources

The following cluster resources can include both hardware resources and software resources:

  • Disks
  • Volume groups
  • Logical volumes
  • File systems
  • Service IP labels or addresses
  • Applications
  • Tape resources

A processor running PowerHA SystemMirror owns a user-defined set of resources: disks, volume groups, file systems, IP addresses, and applications. For the purpose of keeping resources highly available, sets of interdependent resources might be configured into resource groups. Resource groups allow you to combine related resources into a single logical entity for easier configuration and management. The PowerHA SystemMirror software handles the resource group as a unit, thus keeping the interdependent resources together on one node and keeping them highly available.