Overview for resource groups

PowerHA® SystemMirror® organizes resources into resource groups. Each resource group is handled as a unit that contains shared resources such as IP labels, applications, file systems, and volume groups. You define the policies for each resource group that define when and how it will be acquired or released.

In Initial cluster planning, you made preliminary choices about the resource group policies and the takeover priority for each node in the resource group node lists. In this section you do the following:

• Identify the individual resources that constitute each resource group.
• For each resource group, identify which type of group it is: concurrent or nonconcurrent.
• Define the participating node list for the resource groups. The node list consists of the nodes assigned to participate in the takeover of a given resource group.
• Identify the resource group startup, fallover, and fallback policy.
• Identify applications and their resource groups for which you want to set up location dependencies, parent-child dependencies, or both.
• Identify the intersite management policies of the resource groups. Are there replicated resources to consider?
• Identify other attributes and runtime policies to refine resource group behavior.

The following terms are used in this section:

• Participating node list. A list of nodes that can host a particular resource group, as defined in the participating node names for a resource group in SMIT.

  Be aware that the combination of the different resource group policies and the current cluster conditions also affect the resource group placement on the nodes in the cluster.

• Home node (or the highest priority node for this resource group). The first node that is listed in the participating node list for any nonconcurrent resource groups.

PowerHA SystemMirror resource groups support NFS file systems.