Dell EqualLogic PS6100 series Configuration Manual page 56

Figure 14 Replica Reserve, Local Reserve, and Delegated Space
Auto replication requires reserved disk space on both the primary and secondary groups. The amount
of space required depends on several factors:
•
Volume size.
•
The amount of data that changes (on the source volume) between each replication period.
•
The number of replicas that need to be retained on the secondary site.
•
If a failback snapshot is retained on the primary group.
The default values that appear in Group Manager are sufficient to ensure that enough space is
reserved for at least one successful replication, even if the entire contents of a volume are altered
between replicas. Initial replication of a volume will cause the complete contents of the volume to be
copied to the secondary group. Subsequent replication events will copy only the changed data. The
recommended and space efficient guidelines for sizing replication reserves and delegated space are
presented in Table 20.
March 2013 Dell EqualLogic Configuration Guide v14.1 6-47