Solaris Volume Manager Three-Mediator Support

Sun Cluster software supports mediators for three-room campus cluster configurations that use Solaris Volume Manager or multi-owner Solaris Volume Manager for Sun Cluster. A two-room (two-node) campus cluster can work with a third mediator host outside the cluster. The third mediator host does not have to be attached to the shared storage that contains the disk set for which the host is a mediator.

The mediator host uses Solaris Volume Manager to facilitate automatic recovery for a two-room campus cluster by tracking which mirrored half of the storage is the most up to date. The third mediator then provides mediator quorum to allow Solaris Volume Manager to recover from a destroyed room.

Use the following guidelines to configure dual-string mediators:

• A disk set can have up to three mediator hosts

• The mediator host no longer needs to be part of the cluster

• Mediators that are configured for disk sets must meet the existing two-string disk set criteria

• The entire campus cluster can have more than two nodes

• An N+1 cluster and other topologies are permitted

To add the third mediator host, follow the instructions in How to Add Mediator Hosts in Sun Cluster Software Installation Guide for Solaris OS. See the appropriate documentation for Sun Cluster 3.1 or Sun Cluster 3.2 software.