A Replicated Volume Group (RVG) on the Primary host and its counterparts on the Secondary hosts make up a Replicated Data Set (RDS). An RDS is not a Volume Manager object but a concept used in VVR. An RDS enables grouping of the RVG on the Primary and its counterparts on the Secondaries.
Most VVR commands operate on an RDS, that is, the Primary RVG and all the Secondaries in the RDS. You can issue VVR commands from any host in an RDS unless otherwise noted. VVR performs the appropriate tasks on the required hosts in the RDS.
The concept of Primary host and Secondary host is used only in the context of a particular Replicated Data Set (RDS). A system can simultaneously be a Primary host for some RDSs and Secondary host for others. This allows for very flexible replication configurations.