Advantages of mirrored HA pairs

Data mirroring provides additional data protection in the event of disk failures and reduces the need for failover in the event of other component failures.

Mirroring your data protects it from the following problems that would cause data loss without mirroring:

  • The failure or loss of two or more disks in a RAID4 aggregate
  • The failure or loss of three or more disks in a RAID-DP (RAID double-parity) aggregate
  • The failure of an array LUN; for example, because of a double disk failure on the storage array
  • The failure of a storage array

The failure of an FC-AL adapter, SAS HBA, disk shelf loop or stack, or disk shelf module does not require a failover in a mirrored HA pair.

Similar to standard HA pairs, if either node in a mirrored HA pair becomes impaired or cannot access its data, the other node can automatically serve the impaired node’s data until the problem is corrected.