This category covers the data stores used by your WebSphere Application Server applications. Unless your applications serve only static information, these resources are usually quite dynamic. You should back these up the same way you back up other business data on your system. These resources are suited for inclusion in a regularly scheduled backup.
For session recovery support, WebSphere Application Server provides distributed session support in the form of database sessions. You can use session recovery support when the user's session data must be maintained across a server restart or when the user's session data is too valuable to lose through an unexpected server failure.
All the attributes set in a session must implement java.io.Serializable if the session requires external storage. In general, consider making all objects held by a session serialized, even if immediate plans do not call for session recovery support. If the Web site grows, and session recovery support becomes necessary, the transition occurs transparently to the application if the sessions only hold serialized objects. If not, a switch to session recovery support requires coding changes to make the session contents serialized.