With Continuous Access Journal (Cnt Ac-J), you create and maintain a remote copy of a data volume on a P9500 system. The remote copy is a block-for-block copy of the local storage volume. Remote data is consistent with local data and therefore available for recovery of the local volume should the need arise.

When a pair is created, the remote system will contain an asynchronous, block-for-block copy of the local storage volume. Impact on host I/O and the primary storage system is limited, since updates sent to the primary volume are also copied to a local journal volume. The remote system “pulls” data from the journal volume across the communication link to the backup-volume. The primary system is free to perform its role as a transaction processing resource rather than as replication engine.