I've looked at the thread dumps provided and they all show the similar signs: "This thread dump contains monitors without a locking thread information. This means, the monitor is hold by a system thread or some external resource. You should check the monitors without locking threads for more information. If you see many monitors having no locking thread, this usually means, the garbage collector is running. In this case you should consider analyzing the Garbage Collector output. " Effectively, this means that GC has it. Are these machines multi core? What are the startup options you're using? Did you enable GC logging? Prabhat, I thought we went through similar situation when you're testing 1 node scenarios, didn't we? I think I suggested that you use tools like TDA to discover scenarios like this. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4170076#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...