How to debug WebLogic 503 Errors under load
I am loadtesting a system, part of which includes a WebLogic 9.2 system. Multiple other servers are also involved as back ends to what is deployed on WebLogic.
I have a simulator that simulates the load that the system has to handle. It sends many requests to an application running on the WebLogic server.
We are very close to handling the required load - except that occasionally there may occur short bursts, around 10 seconds in duration max, during which all requests sent by the simulator to WebLogic fail with 503 Errors. After this burst ends, all requests once again are successfully handled by the system for much longer intervals.
I am quite unable to figure out what is actually going on when this happens. Is there a setting that would allow high level logging of 503 errors and high level logs of other events occurring on the server (preferably in the same log but perhaps not), so that we might correlate the 503s with whatever other event is putting load on the server?