Directory services can be replicated to distribute transactions across different servers, providing high availability. Directory Server provides various strategies for replication of services, including the following:
Multiple databases. Stores different portions of a directory tree in separate databases.
Chaining and referrals. Links distributed data into a single directory tree.
Single master replication. Provides a central source for the master database, which is then distributed to consumer replicas.
Multi-master replication. Distributes the master database among several servers. Each of these masters then distributes their database among consumer replicas.
Availability strategies for Directory Server is a complex topic that is beyond the scope of this guide. The following sections, Single Master Replication and Multi-Master Replication provide a high-level view of basic replication strategies. For detailed information see Chapter 12, Designing a Highly Available Deployment, in Sun Java System Directory Server Enterprise Edition 6.0 Deployment Planning Guide.