3 Replies Latest reply: May 4, 2012 6:46 AM by Radoslav Husar RSS

    Jboss session data store and failover handling

    Hemant Kumar Newbie

      Where does the jboss store the session data? And if it stores in-memory then how does it do the session management in clustered environment? I mean how the fail over is taken care of without loosing the sessioncontext. Appreciate your help.

       

      Thanks,

      Hemant

        • 1. Re: Jboss session data store and failover handling
          Radoslav Husar Master

          Where does the jboss store the session data?

          In memory. You can also configure passivation for some sessions to be spilt to the disk.

           

          fail over is taken care of without loosing the sessioncontext

          The sessions are replicated to other servers that will have a copy of data in case failover happens. The session ID is then the key so the server knows which session failed over.

           

          Rado

          • 2. Re: Jboss session data store and failover handling
            Hemant Kumar Newbie

            Agreed with the first part that it stores the session in memory.

             

            But for failover I've my doubts because of performance degradation -- lets assume I'm having 100 instances in a clusted so for every session update for each user data has to be replicated to 100 different servers, and with large number of users I think servers will just be busy only in replicating the session. It's an opinion though

            • 3. Re: Jboss session data store and failover handling
              Radoslav Husar Master

              But for failover I've my doubts because of performance degradation -- lets assume I'm having 100 instances in a clusted so for every session update for each user data has to be replicated to 100 different servers, and with large number of users I think servers will just be busy only in replicating the session. It's an opinion though

              Absolutely true -- but its a very very silly and unrecommended setup :-)

               

              It would in theory mean you have 9 900% data redundancy meaning 99 server instances can crash at the same time in order to not lose any data. In other words, this makes no sense at all.

               

              The way to do this, is to

              • use buddy replication (number of buddies) in AS5 and distributed  mode in AS6/7,
              • or split into smaller clusters each using total/full replication and configuring domains on the load balancer

               

              Rado