Planning cluster sites

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PowerHA® SystemMirror® clusters can be used within a single site or multiple sites for disaster recovery.

If you have multiple sites, you can use the following PowerHA SystemMirror Enterprise Edition features for disaster recovery:

  • PowerHA SystemMirror Enterprise Edition for AIX® includes options for supporting replication technologies that are available from various storage subsystems.
  • PowerHA SystemMirror Enterprise Edition for AIX for GLVM provides host-based replication over TCP/IP networks.

PowerHA SystemMirror 7.1.2, or later, supports different types of definitions for sites and site-specific policies for high availability and disaster recovery (HADR). You can define multiple sites in both PowerHA SystemMirror Standard Edition for AIX and PowerHA SystemMirror Enterprise Edition for AIX.

PowerHA SystemMirror uses Cluster Aware AIX (CAA) for cluster communication and cluster health management.

You can use PowerHA SystemMirror management interfaces to create the following multiple-site solutions:
Stretch clusters
Contains nodes from sites that are located at the same geographical locations. Stretched clusters must share a repository disk across all nodes in the site. Stretched clusters do not support HADR with Storage Replication Management. To use stretch clusters, your network environment must support multicast-based communication.
Linked clusters
Contains nodes from sites that are located at different geographical locations. Linked clusters use a separate repository disk. Linked clusters support cross-site LVM mirroring and HyperSwap®. In linked clusters, CAA uses unicast packets to communicate and manage the sites between the independent CAA clusters.