7.3.3 Redundancy

In an LPAR-based environment, even the simplest application can use clustering and have its own redundant LPARs to ensure continuity of service in the event of a serious error. This ability raises the standards of application deployment.

In order to implement physical redundancy (continuity of service in the event of physical machine failure), LPARs should be split across separate physical System p servers. Figure 7-3 depicts the deployment of our earlier applications alpha and beta on a pair of System p servers.

Figure 7-3 Deployment of applications alpha and beta in a redundant configuration

Each application has its own logical partitions, and the partitions are split across the two servers. clustering is used to ensure that if one application server instance is unavailable, requests will not be routed to that LPAR.