Replication and duplication of backups

When replicating or duplicating images between pools, data commonality should be considered. Consider the case of two sites replicating bi-directionally. Each site has clients that are protected and sends those backups to the other site. If there is common data between the sites (for example, copies of databases), the data will not have to be written at the remote site, since it already exists in the storage pool. This can result in significant space savings depending on the level of data commonality. If there are large quantities of common data, this should be considered when sizing. If there is limited or no commonality, then the space consumed on the remote pool will be about the same as the space consumed locally for those backups.