Benefits of Replication

Replication is deployed for one or both of the following reasons:

Improved availability: Replication can make a system more robust by enabling the directory on one server to failover to an alternative server. Applications can continue working, because as there are alternate DSAs or servers in the network that can serve the same parts of the namespace.
Improved performance: Replication can place frequently accessed information closer to where it is needed, which improves response times and allows the load to be shared between DSAs.