Sun GlassFish Enterprise Server 2.1 High Availability Administration Guide

Overview of Session Persistence and Failover

Enterprise Server provides high availability session persistence through failover of HTTP session data and stateful session bean (SFSB) session data. Failover means that in the event of an server instance or hardware failure, another server instance takes over a distributed session.


A distributed session can run in multiple Sun GlassFish Enterprise Server instances, if:


When a session fails over, any references to open files or network connections are lost. Applications must be coded with this restriction in mind.

You can only bind certain objects to distributed sessions that support failover. Contrary to the Servlet 2.4 specification, Sun GlassFish Enterprise Server does not throw an IllegalArgumentException if an object type not supported for failover is bound into a distributed session.

You can bind the following objects into a distributed session that supports failover:

You cannot bind the following object types into sessions that support failover:

In general, for these objects, failover will not work. However, failover might work in some cases, if for example the object is serializable.