Figure 6-4“Multi-master replication configuration B (four suppliers)” illustrates a topology where each supplier server feeds data to two other supplier servers (which also function as consumers). Only eight replication agreements exist between the four supplier servers, compared to the twelve agreements shown for the topology in Figure 6-3“Multi-master replication configuration A (four suppliers)”. This topology is beneficial where the possibility of two or more servers failing at the same time is negligible. Because each supplier only supplies two other servers, such a configuration is useful in reducing the network traffic and reducing server load.

Figure 6-4 Multi-master replication configuration B (four suppliers)

NOTE:

HP-UX Directory Server supports a maximum of four supplier servers in any replication environment. However, the number of consumer servers that hold the read-only replicas is unlimited.

The following diagram illustrates the replication traffic in an environment with two suppliers (read-write replicas in the illustration), and two consumers (read-only replicas in the illustration). This figure shows that the consumers can be updated by both suppliers. The supplier servers ensure that the changes do not collide.

78 Designing the replication process