HP 3PAR Operating System Software - Manual (Page 20)

Figure 5 M-to-N Remote-Copy Configuration—Example
Synchronous Long Distance Configuration
A synchronous long distance (SLD) remote-copy configuration is composed of two targets: one
synchronous group and one asynchronous periodic group. In SLD remote copy, one primary system
uses two backup systems and participates in two remote-copy pairs, one for each backup system.
In an SLD configuration, remote copy volume groups from the primary system are replicated to the
two separate target arrays simultaneously. Data is replicated to one target in synchronous mode
and to the second in asynchronous periodic mode. The target systems must each have appropriate
network connections to the source systems to support the replication mode being used. There is no
requirement that the closer of the two secondary systems be replicated to synchronously.
While there is no requirement that the closer of the two secondary systems be replicated to
synchronously, HP recommends it, with remote copy set up in asynchronous periodic mode between
the primary system and the secondary system that is physically farther apart (and therefore likely
to share a lesser connection).
20 Selecting a Remote-Copy Configuration