I set up cluster both in web and app server tier.I got a question.let's say there is a stateful session bean instanced by client and runing on server1,once server1 failed,the load balancer transfer the client connection to server2,does the session bean's state maintained on server2?
in another word,say the session bean has a instance variable, s=100,once server1 failed,does client still get s=100 from server2?
Fail-over for Stateful Session Beans (SFSB) is ugly.
The only way it can work is if every server in the cluster maintains its own copy of the SFSB, and keeps it up-to-date. That means every update to Server1 must be replicated on Server2, because if Server1 crashes, this is the only way to ensure that the copy of the SFSB on Servet2 is correct.
Needless to say, this has poor performance, which is why most vendors recommend against clustering SFSB.