Administrator Guide

Synchronous replication features
16 Dell EMC SC Series: Synchronous Replication and Live Volume | CML1064
3.4 Multiple replication topologies
Dell extends synchronous replication support beyond just a pair of SC Series volumes residing in the same or
different sites. A choice of two topologies or a hybrid combination of both is available.
3.4.1 Mixed topology
The mixed topology, also known as 1-to-N (N=2 as of SCOS 6.5), allows a source volume to be replicated to
two destination volumes where one replication is synchronous or asynchronous and the additional replications
are asynchronous. The maximum number of additional replications is set by the value of N. This topology is
useful when data must be protected in multiple locations. If data recovery becomes necessary, a flexible
choice of locations is available for recovery.
Mixed topology
If the volume replication source becomes unavailable, volume replication stops.
The source volume of a replication becomes unavailable and replication stops
For recovery purposes, the replica can be activated and mapped by Dell Storage Manager to a storage host
(for instance, at a disaster recovery site).
Furthermore, in a mixed topology, a replica volume may be configured to replicate to another one of the
replicas (asynchronous or synchronous) without having to reseed a majority of the data both volumes would
already have before the original source volume became unavailable. This may be useful where two or more
disaster recovery sites exist.