Hi

In Our setup, we have WebSphere cluster having 4 servers. front face we have IBM HTTP Server ( Intelligent management ).. I am noticing all the sessions are locked into any one of the server ( changing the server after restart happened ). How to make the session to be distributed evenly ( almost ) to all the servers.. here rest of the three servers are almost free ( 90% ), as per the configuration the cluster members configuration /runtime weight is 2.  Need your suggestion to improve the performance.

Bhaskar,

It doesn't sound as if the IBM HTTP Server is performing Load Balancing correctly.  Here is a link (IHS Load Balancing) to an IBM Support article that may help.  

Regards,

Glen Brumbaugh

IBM Champion (Cloud)

The behavior you describe *might* be normal if 90% of you users sign-in while only one server is running. In this case the users stick to the WAS server due to session affinity maintained by the plugin. However I think that is quite unlikely.

Als Glen pointed out you should check the plugin-cfg.xml for you HTTP servers. Especially the following properties might be interesting:

• LoadBalanceWeight
• IgnoreAffinityRequests
• LoadBalance

Depending on your applications session usage you might consider changing the later two (is assume that the weight is the same for all?). Especially the IgnoreAffinityRequests you should take a look at as this defaults to "true" in certain releases what is not a good choice if you have many session affinity related requests. In this case you can try changing the value to false. See http://www-01.ibm.com/support/docview.wss?uid=swg21318463 for more information on recommended plugin-cfg.xml settings and some background information.

Please see also https://developer.ibm.com/answers/questions/246181/why-does-the-websphere-plugin-not-load-balance-tra/ as a good reference.

How many HTTP Servers do you have and are they on the same machine as WAS? How are you distributing load to HTTP Server?

--Sunit