Asynchronous remote mirroring

Asynchronous mirroring enables you to attain high availability of critical data through a process that asynchronously replicates data updates that are recorded on a primary storage peer to a remote, secondary peer.

With synchronous mirroring, host writes are acknowledged by the storage system only after being recorded on both peers in a mirroring relationship. This yields high currency of mirrored data (both mirroring peers have the same data), yet results in less than optimal system responsiveness because the local peer cannot acknowledge the host write until the remote peer acknowledges it. This type of process incurs latency that increases as the distance between peers increases.

XIV features both asynchronous mirroring and synchronous mirroring. Asynchronous mirroring is advantageous in various use cases. It represents a compelling mirroring solution in situations that warrant replication between distant sites because it eliminates the latency inherent to synchronous mirroring, and might lower implementation costs. Careful planning of asynchronous mirroring can minimize the currency gap between mirroring peers, and can help to realize better data availability and cost savings.

With synchronous mirroring (first image below), response time (latency) increases as the distance between peers increases, but both peers are synchronized. With asynchronous mirroring (second image below), response time is not sensitive to distance between peers, but the synchronization gap between peers is sensitive to the distance.

Note: Synchronous mirroring is covered in Synchronous remote mirroring.