Techniques for replicating session data include distributing: to all nodes in a cluster; to a subset of the nodes in the cluster; to a database; to a cluster server; etc. etc. To this range of solutions, Cometd/Bayeux now adds the possibility of using the client machine to store a replicated session.

I have blogged about a prototype BayeuxSessionManager for Jetty.

While it sounds strange, if you think about it, the client machine is the perfect place to store a replicated copy of the server session data. It is a machine that is always in communication with the correct web server, and if the client machine crashes, the session is by definition over so you don’t need to timeout the replicated data. Client machines scale with the number of users, so if you have more users then you have more machines available to store replicated session.