Replication is a data synchronization mechanism that ensures that updates made to a database are automatically replayed to other servers. Replication improves data availability when unforeseen or planned outages occur, and improves search performance by allowing client requests to be distributed across multiple servers.
By default, all Directory Servers participating in replication are writable, so that LDAP clients can perform updates at any of these Directory Server instances. These updates will be propagated to the other servers automatically in the background and applied in the same order as the updates were entered. The replication process flow is designed to immediately propagate changes to the other replicas in the topology with little or no latency.
The following figure demonstrates the basic flow of replication.