Advantages of stretch MetroCluster configurations

MetroCluster configurations provide the same advantages of mirroring as mirrored HA pairs , with the additional ability to initiate failover if an entire site becomes lost or unavailable.

For MetroCluster configuration on disks, the advantages of a stretch MetroCluster configuration are as follows:

  • Your data is protected if there is a failure or loss of two or more disks in a RAID 4 aggregate or three or more disks in a RAID-DP aggregate.
  • The failure of an FC-AL adapter, loop, or IOM module does not require a failover.
For MetroCluster configurations with systems using array LUNs, the advantages of a stretch MetroCluster configuration are as follows:
  • For RAID 0 aggregates, your data is protected if there is a failure of a storage array or loss of an array LUN on one of the storage arrays in the MetroCluster configuration.

In addition, a MetroCluster configuration provides the cf forcetakeover -d command, giving you a single command to initiate a failover if an entire site becomes lost or unavailable. If a disaster occurs at one of the node locations and destroys your data there, your data not only survives on the other node, but can be served by that node while you address the issue or rebuild the configuration.