Your campus cluster must use SAN-supported storage devices for shared storage. When planning the cluster, ensure that it adheres to the SAN requirements for all storage connections. See the SAN Solutions documentation site for information on SAN requirements.
You must mirror a campus cluster's shared data. If one room of the cluster is lost, another room must be able to provide access to the data. Therefore, data replication between shared disks must always be performed across rooms, rather than within rooms. Both copies of the data should never be in a single room. Host-based mirroring is required for all campus cluster configurations, because hardware RAID alone does not lend itself to providing data redundancy across rooms.
In addition to mirroring your data, you can add storage-based data replication if you judge that your campus cluster needs the additional data redundancy. See Appendix A, Data Replication Approaches for more information on storage-based data replication.