Topic
3 replies Latest Post - ‏2011-03-16T21:09:11Z by bkmartin
SystemAdmin
SystemAdmin
25 Posts
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Pinned topic How to use DataPower XC10 for session persistance/failover?

‏2011-03-12T17:11:22Z |
Hello All!

The following topology has been built: cell with cluster comprised of two WAS servers. Nodes belong to "ReplicationZone" Node group. There is XC10 appliance ver 1.0 in the mix. On the application level Session management is enabled and session persistence is provided by DataPower XC10 appliance.

The sample application is session-aware with counter stored in the session object. The app comprised of login servlet, couple "worker" servlets and logoff servlet to invalidate session.

I use JMeter to run application. I can see Grid to be populated at runtime and I know that both my servers are load-balanced by HTTP server as I can see each of them serve the requests generated by JMeter.. No memory-to-memory replication is set up.

Obviously, what I want to see is the session failover. While app is running in JMeter loop (worker servlets are invoked every 2-3 seconds), one of the servers gets shut down. I expect to see the second server to pickup new requests and reuse session data persisted in the appliance. Unfortunately I just see the session dropped – as if no replication is setup. What else is needed to be setup so sessions will survive the server shutdown?

Thank you!
Updated on 2011-03-16T21:09:11Z at 2011-03-16T21:09:11Z by bkmartin
  • bkmartin
    bkmartin
    11 Posts
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    Re: How to use DataPower XC10 for session persistance/failover?

    ‏2011-03-13T01:45:41Z  in response to SystemAdmin
    Are you running XC10 firmware 1.0.0.4 with the XC10 Client 1.0 (XS 7.1.0.1) updated on 12/17/2010 posted here: http://www-01.ibm.com/support/docview.wss?uid=swg24027148

    There is nothing special you need to do to enable session failover as long the application is configured to use the XC10 for session persistence in the WAS WebUI. What version of WAS is being utilized? Are you using the WAS plugin as the front end load balancer for this scenario?

    I suspect we might need to look at session=all=enabled traces on your WAS servers to see why you are not seeing the sessions failover from WAS server to the other.

    Brian
  • SystemAdmin
    SystemAdmin
    25 Posts
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    Re: How to use DataPower XC10 for session persistance/failover?

    ‏2011-03-14T20:00:06Z  in response to SystemAdmin
    Thank you, Brian for response.

    As soon as I bounced the servers I can see the session failover working.

    The next related question is why I don't see sessions coming back to the initial server.

    Here is the scenario:

    Two WAS servers fronted with IHS. Two browser-based clients access the application deployed to the cluster. Each client is served by one of servers. I cat track this using com.ibm.websphere.runtime.ServerName. Session affinity works fine.

    Now I take down one server and can see that all requests are served by the remainin server. The expected behavior (I may be wrong here drawing parallels with memory-to-memory replication) whould be that when I bring up the failed server back the session initially hosted on that server would come back. I don't see this happening. After session failed over to another server it does not come back to the server where it was started. Is this correct behavior?

    Thank you!
    • bkmartin
      bkmartin
      11 Posts
      ACCEPTED ANSWER

      Re: How to use DataPower XC10 for session persistance/failover?

      ‏2011-03-16T21:09:11Z  in response to SystemAdmin
      The current XS/XC10 client will not return the session to the original server when it comes back. As a result of your query, we are now investigating changing that behavior.

      Thanks,
      Brian