Learn more about creating clusters

A cluster is a loosely coupled collection of independent systems (nodes) that are organized into a network for sharing the resources and communicating with each other. If a cluster node is not able to provide services, PowerHA® SystemMirror defines relationships among the operating systems so that the peer cluster nodes provide those services.

Before you start, you must complete the following prerequisites:
  • Install PowerHA SystemMirror software on all the nodes that you want to include in the cluster.
  • Ensure that all nodes that you want to include in the cluster meet the following requirements:
    • They have the same AIX® version installed on them.
    • They have the same version and edition of the PowerHA SystemMirror installed on them.
    • They have at least one storage disk in common among them to be used exclusively for the cluster repository. This repository contains configuration and other important data that all nodes need to be able to access.
  • Connect and configure all the IP network interfaces.
  • Discover all nodes in your subnetwork by using the Discovery task in the IBM® Systems Director.
  • Request access to nodes that have a status of no access by using the Request Access task in the IBM Systems Director.
  • Collect information to define an active communication path to the takeover node.
The wizard automatically discovers and configures the various communication paths between the local node and the takeover node. If the local node and the takeover node have IP aliases associated with them, and the aliases are reachable from the local node, the wizard automatically configures the aliases as PowerHA SystemMirror persistent IP addresses.
Note: You can also supply specific values for persistent IP addresses for the local node and the takeover node, if you prefer.
If you are using PowerHA SystemMirror 7.1 Enterprise Edition, the nodes that you want to include in the cluster must meet the following additional requirements:
  • The local node must have an active communication path to the takeover node.
  • The local node and the takeover node must have the required filesets installed on them.
    Note: start of changeReview the PowerHA SystemMirror release_notes file in the /usr/es/sbin/cluster/ directory for a full list of filesets, further instructions, and the latest information on requirements or known issues.end of change

For more information about creating clusters, see the Create a Cluster topic in the AIX information center.