Webserver Plugin not choosing secondary server

Question

Has anyone any idea why my web server plugin will sometimes choose a secondary server and sometimes not?
I've got no cluster issues (well, no lost multicast packets) that I can see, the plugin debug information indicates that servers are available, yet I only have a single JVM chosesn and stored in my cookie
This is what I'm seeing from the cluster debug information - just a primary chosen and everything else looks normal.
Has anyone any suggestions?
Pete
Properties loaded from path: '\\?\C:\IISPlugin\PRD\iisproxy.ini'
Query String: '__WebLogicBridgeConfig'
WebLogic Cluster List:
1. Host '172.23.1.12' Port: 7030 SecurePort: 7031 Primary
Dynamic Server List:
1. Host: '172.23.1.12' Port: 7030 SecurePort: 7031 Status: OK
2. Host: '172.23.1.12' Port: 7040 SecurePort: 7041 Status: OK
3. Host: '172.23.1.11' Port: 7010 SecurePort: 7011 Status: OK
4. Host: '172.23.1.11' Port: 7020 SecurePort: 7021 Status: OK
Static Server List:
1. Host: '172.23.1.11' Port: 7010 SecurePort: 7010
2. Host: '172.23.1.11' Port: 7020 SecurePort: 7020
3. Host: '172.23.1.12' Port: 7030 SecurePort: 7030
4. Host: '172.23.1.12' Port: 7040 SecurePort: 7040

Answer 1

Thanks Pete. If you are saying that your JSESSIONID cookie only contains a single JVM ID, then this is usually an indication that the WL cluster node that created the session did not successfully create a replicated session on its chosen secondary server (or it believes it is not configured to replication sessions at all -- although your config looks good). As you probably know, it is the WL managed server that determines if a secondary JVM ID is populated in the session cookie based upon successful replication. The web server plugin will only use the secondary JVM ID in the session cookie if it fails to communicate with the primary server identified in the session cookie. If the web server is able to communicate with the primary owner of the session (dynamic server list includes the server and network is good) it will always route the request to the primary.
Couple of other baseline questions:
(a) what version of weblogic are you running?
(b) have you been able to confirm that replication of session data is truly occuring between your nodes (depending on your version of WL, this can be verified on the admin console by clicking on Clusters, click on your cluster name, then select the Monitoring tab. If replication of session information is occuring you will see for each server that has an active session it will display information in the form "managed_server_name:number_of_sessions" under the "Secondary Distribution Names" column. This is an indication of sessions that have been replication If replication is not enabled or not working properly, this column will be blank). You can also enable cluster debugging to see replication messages logged to your server log. In the admin console go to Servers, pick a managed server, click on the Debug tab and expand the "weblogic -> core " part of the tree and select "cluster". This will enabled all cluster debug messaging.