The Application Server includes load balancing for HTTP, IIOP, and JMS clients; HTTP session failover support; EJB clustering and failover support; highly available EJB timers; distributed transaction recovery; support for rolling application upgrades; and a high availability database for storing the transient state of J2EE applications.
Availability allows for failover protection of Application Server instances in a cluster. If one Application Server instance goes down, another Application Server instance takes over the sessions that were assigned to the unavailable server. Session information is stored in the HADB. HADB supports the persistence of HTTP sessions, Stateful Session Beans, and Single Sign On credentials.