A database that participates in replication is defined as a replica.
Master or read-write replica. A read-write database that contains a master copy of the directory data. A master replica can process update requests from directory clients. A topology that contains more than one master is called a multi-master topology.
Consumer replica. A read-only database that contains a copy of the information in the master replica. A consumer replica can process search requests from directory clients but refers update requests to master replicas.
The following figure illustrates the role of each of these replicas in a replication topology.
The previous figure is for illustration purposes only and is not necessarily a recommended topology. Directory Server supports an unlimited number of masters in a multi-master topology. A master-only topology is recommended in most cases.