Network Deployment (Distributed operating systems), v8.0 > Reference > Administrator best practices
Session recovery support
For session recovery support, WAS provides distributed session support in the form of database sessions and memory-to-memory replication. We 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 website 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.
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Distributed environment settings
Sessions
Distributed sessions
Task overview: Managing HTTP sessions