About the cascading failure scenario

If the performance of a database is unacceptable with two database groups running on a single server, the SystemZones policy can help expedite performance. Failing over a database group into the application zone has the effect of resetting the group's preferred zone. For example, in the above scenario Database3 was moved to LargeServer1. The administrator could reconfigure the application zone to move two application groups to a single system. The database application can then be switched to the empty application server (MedServer1 - MedServer5), which would put Database3 in Zone1 (application zone). If a failure occurs in Database3, the group selects the least-loaded server in the application zone for failover.