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33 PS Series Asynchronous Replication Best Practices and Sizing Guide | BP1012
Navigation tip: SAN Headquarters (primary) > Capacity > Pools (menu select pool)
Reported Size and In use capacities for the two volumes
The local replication reserve should accommodate both the original usable space in the volume and the
maximum change rate. In addition, typically the fast-failback snapshot is kept, which will keep the most
complete replica to allow the partners to synchronize back only the changes that occurred during disaster
recovery (promote to volume on the secondary). For these reasons, 200 percent of the reported size is
recommended for each volume.
Applying this to our example, 200 percent of 420 GB equals 840 GB x 2 volumes, or 1680 GB total for local
reserves.
This space will need to be accounted for locally. Keep in mind this is in addition to any local snapshots that
may be needed on the primary group. Since there is already 840 GB of reported size on the primary group, it
needs to be verified that an additional 840 GB is available on the PrimaryGroup’s hybrid pool.