Use a LUN device as the failover unit for each BCC-enabled cluster resource. Multiple pools per LUN are possible, but are not recommended. A LUN cannot be concurrently accessed by servers belonging to different clusters. This means that all resources on a given LUN can be active in a given cluster at any given time. For maximum flexibility, we recommend that you create only one cluster resource per LUN.

We recommend that you use only one LUN per pool, and only one volume per pool. If you use multiple LUNs for a given shared NSS pool, all LUNs must fail over together.

Data must be mirrored between data centers by using host-based mirroring or storage-based mirroring. Storage-based mirroring is recommended.

When using host-based mirroring, make sure that the mirrored partitions are accessible for the nodes of only one of the BCC peer clusters at any given time. If you use multiple LUNs for a given pool, each segment must be mirrored individually. In large environments, it might be difficult to determine the mirror state of all mirrored partitions at one time. You must also make sure that all segments of the resource fail over together.