On 17/06/2011 09:42, Pontus wrote: > Hello, > > The Tomcat 6.0 Clustering/Session Replication HOW-TO states "Make sure > that your loadbalancer is configured for sticky session mode". > > However if I configure my Tomcat cluster to have session replication, why > would sticky sessions be required ?
If you use the Backup manager, you must use sticky sessions since the session is only backed up to a single node (selected at random for each session) in the cluster. If you use the delta manager, sticky sessions are advisable for several reasons: - Parallel requests. If a browser issues multiple requests in parallel and these are handled by different nodes one request might not see that session changes triggered by a different request and that might be an issue. - Performance. Without sticky sessions, you need to use use synchronous session replication to ensure all the other nodes in the cluster have the updates before the next request is issued. That takes time. - Debugging. Trying to figure out what went wrong is usually hard enough without each request going to a different node. Mark > I can see cases where sticky sessions are for performance a better option, > I might have some DB cache not connected to the session or some > non-serialized data. However provided that I store all session data in the > session object and have all data serializable is sticky session mode in > the LB really a requirement and if so why ? > > Best regards > Pontus Ullgren > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org > For additional commands, e-mail: users-h...@tomcat.apache.org > --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
