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Clustering In EJB

suman paul
Greenhorn

Joined: Feb 19, 2003
Posts: 19
Could any one tell me how horizontal scaling works?
Suppose i have S1-->S2--->s3--->S4--->s5-->DBServer
Now if a client is on transaction and the session is active on the first
server .Now suudenly the S1 fails how does the session gets saved / propagated to S2 to take over or what is the way to handle this kind of failover w/c client won't get affteceted but the transaction would go safely
with session data.
Pls explain the config in perspective of Weblogic & Websphere & the concept.
Lasse Koskela
author
Sheriff

Joined: Jan 23, 2002
Posts: 11962
    
    5
Now if a client is on transaction and the session is active on the first server. Now suddenly S1 fails how does the session gets saved / propagated to S2 to take over or what is the way to handle this kind of failover w/c client won't get affected but the transaction would go safely
with session data.

Typically, each server in a cluster has one backup server nominated to which it frequently replicates session state. Either the client-side stub (for EJBs) or the load balancer knows which server is the backup for S1, and once it figures out that S1 is down, it starts forwarding S1's requests to its backup.
Pls explain the config in perspective of Weblogic & Websphere & the concept.

Why don't you take a look at the documentation provided by BEA and IBM...


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