Some tips when debugging WLS cluster stability
In one environment we had problems with cluster stability - and there were unnecessary migrations of JMS Servers.
Here are some settings that gave more info in logs. Set the following for the JVM:
Change the below setting to DEBUG
Home >Summary of Servers >AdminServer >Logging >General >Advanced >Minimum severity to log:
enable below debugs from the weblogic admin console.
Debug >weblogic >core
cluster Collapse Node
DebugAsyncQueue DebugCluster DebugClusterAnnouncements DebugClusterFragments DebugClusterHeartbeats DebugLeaderElection DebugReplication DebugReplicationDetails
Change the logging severity to Debug
Servers-->Server_name-->Logging-->Advanced--> Standard out :Severity level:Debug Log file :Severity level:Debug
Also look at Cluster » Monitoring » Summary to see the number of sent / received / retransmitted. For a healthy system sent and received should be almost same - and retransmissions low.