Session Replication

A method used with Application Load Balancing, to achieve session-failover.

Sessions are replicated to other members of the cluster, each time there is a change in the session data.

With session replication, session-failover is automatic. If an application server goes offline, the load balancer simply sends incoming requests to another server.

The user can be sent to any server, as all servers have a copy of the user's session. Tomcat uses this method with distributable web applications to provide session-failover and enable load balancing.

See Also

• Load Balancing for a general discussion on load balancing
• Application Load Balancing for a comparison of other techniques used to load-balance web applications
• Session Failover
• <distributable> element in web.xml to mark an application as distributable. Contains a list of requirements for a distributable Tomcat application.