What you can expect
The effect that deduplication has on replication and disaster recovery windows can be profound. To start, deduplication means a lot less data needs transmission to keep the DR site up to date so much less expensive wide area network (WAN) links may be used.
Also, replication goes a lot faster because there's less data to send. The length of the deduplication process—beginning to end—depends on many variables including the deduplication approach, the speed of the architecture, and the DR process.
For the most efficient time-to-DR readiness, inline deduplication and replication of deduplicated data yield the most aggressive, efficient results. In an inline deduplication approach, replication occurs during the backup, significantly improving the time by which there's a complete restore point at the DR site or improving time-to-DR readiness. Typically, less than one percent of a full backup actually consists of new, unique deduplicated data sequences, which ensures that data can be sent over a WAN quickly and efficiently.
Aggressive cross-site deduplication, when multiple sites replicate to the same destination, can add additional value by deduplicating across all backup replication streams and all local backups. Unique deduplicated segments previously transferred by any remote site or held in local backup are then used as references to further improve network efficiency by reducing the data to be replicated.
In other words, if the destination system already has a data sequence that came from a remote site or a local backup, and that same sequence is created at another remote site, it will be identified as redundant by the EMC Data Domain system before it consumes bandwidth traveling across the network to the destination system. All data collected at the destination site can be safely replicated off-site to a single location or multiple DR sites.