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8 Using Dell PS Series Asynchronous Replication | TR1052
2.1 Primary and secondary group administration
Because replication involves two groups, group administrators must coordinate their efforts.
To configure groups as replication partners, each administrator needs the following information:
 Group name and IP address of the partner
 Amount of space each group will delegate to the other, if any
 Mutual authentication passwords that enable the two groups to communicate with each other
2.2 Space requirements
Volume replication between partners requires space on both the primary group (the volume location) and
the secondary group (the replica location). These space requirements are classified as follows:
Delegated space (section 5.1.3) on the secondary group, is the amount of space dedicated to storing
replicas from the primary group. All replica reserves are confined to exist within this configured limit.
In PS Series firmware v8 and later, you can assign delegated space for a single partner in multiple pools
(section 5.1.3) and the entire storage space can be used within the group. Delegated space can be
assigned in one, some, or all pools. Prior to PS Series firmware v8, delegated space was restricted to one
storage pool for a particular replication partner. Also, in PS Series firmware v8 and later, you can configure
a mapping between primary pools and secondary pools for initial replica set placement. See Figure 1.
Figure 1 Mapping between primary and secondary pools for initial replica set placement
Local replication reserve on the primary group, is the amount of space reserved in the pool for replication
operations. Local replication reserve keeps track of changes that occur to the volume while it is being
replicated. It also stores a failback snapshot, if you choose to keep one.