Planning the Deployment of LDAP Master and Replica Servers

Language:

Master and replica servers can be deployed in the following ways:

Single-master replication
Floating-master replication
Multi-master replication

The following table compares the three strategies for deploying LDAP master and replica servers.

Table 3-2 LDAP Master and Replica Servers

Strategy	Description	Risks
Single-master replication	One master server exists for a specific network or subnetwork. The master server stores writable copies of the directories. Replica servers store read-only copies. Only the master server can perform write operations.	Single point of failure. If the master server becomes unavailable, no other server can perform write operations.
Floating-master replication	Similar to single-master replication. However, if the master server becomes unavailable, another replica server can perform write operations. The replica server that takes over the write operations is selected based on an algorithm.	Strategy is not flexible for network configuration changes. For example, a network is subdivided into subnetworks. The replica servers on both subnets become master servers. If the subnets are subsequently rejoined over time, the reconfiguration process to redeploy the servers by using the floating-master replication strategy becomes complex.
Multi-master replication	Multiple master servers store read-write copies of the same directories.	Update conflicts of the same directories in the different master servers can occur. An update conflict resolution policy, such as "last writer wins," must be established if this strategy is adopted.

For information about how to set up replica servers, refer to the administration guide for the version of Oracle Directory Server Enterprise Edition that you are using. For large scale enterprise deployments, multi-master replication is the recommended option.