In a Peer Persistence configuration, the LUN on both storage systems is assigned the same WWN. These physically separate volumes with the same WWN allow a host to see the same LUN with different paths. So if a failover occurs, the host can continue its I/O operations uninterrupted.

Failsafe is used to prevent the volumes from becoming writable on both systems simultaneously. Failsafe helps prevent data inconsistency between primary and secondary volumes when the volumes have the same WWN. Failsafe can occur even in non-Peer Persistence configurations, if the volumes have the same WWN.

For example: The primary storage system fails (loses power, crashes, or reboots). The primary Remote Copy groups fail over to the secondary storage system. When the primary storage system comes back up, the volumes in the primary groups are in a failsafe status until the primary storage system determines the status of the secondary storage system.

For example: The primary storage system cannot communicate because the Remote Copy links and Quorum Witness communications are down. A failover to the secondary storage system occurs and all volumes in the primary Remote Copy groups on the primary storage system are placed into a failsafe status.