If you are concerned about performing a switch in the event of a disaster or have very high resiliency requirements you could implement hardware based replication using a IBM Hyperswap configuration, this can ensure that no downtime occurs due to a loss of one storage controller and is a highly resilient option if no data loss is the primary objective.
Many organisations need to meet very stringent recovery time and recovery point objectives, implementing this solution in conjunction with software based replication can remove storage single points of failure and can protect you from complete loss of the live data centre.