Oracle Fusion Middleware Administration Guide for Oracle Directory Server Enterprise Edition

Single-Master Replication Scenario

Because all modifications by client applications are performed on the master replica, the UID uniqueness plug-in should be enabled on the master server. The plug-in should be configured to enforce uniqueness in the replicated suffix. Because the master ensures that the values of the desired attribute are unique, you do not need to enable the plug-in on the consumer server.

Enabling the UID uniqueness plug-in on the consumer of a single master does not interfere with replication or normal server operations. However, it might cause slight performance degradation.