Using HDR in a Hierarchical Tree Topology

With a hierarchical tree topology, parent servers are good candidates for using HDR to provide backup servers. The following example is based on the example in Figure 11.

If China fails, then Beijing and Shanghai can no longer replicate with other servers in the replication system; Guangzhou and Hong Kong can only replicate with each other. However, if China participated in HDR, when it failed, the secondary server would replace it and replication could continue, as illustrated in Figure 16.

Figure 16. Hierarchical Tree Topology with HDR

In this example, Asia and Guangzhou, which are also parent servers, could also benefit from using HDR to ensure high availability.