I was doing performance testing on an application in my organization with load of 250 concurrent users with ramp up of 50,100 then 250. I am using IBM Rational performance tester(RPT). I have used IE browser for recording the scripts.
The pattern which I have observed is that when 250 users were running for some time(nearly 14 minutes) after ramp up stage, the response time graph decreased sharply. When I check the application under test on browser it showed "Page cannot be displayed". After some time the response graph again began to rise and when I check the application under test on browser it became up again. This behavior was occurring in repeated manner. I asked application server handling team whether they have restarted the application but they told me that they have not done so.
The application under test was becoming up on its own.
The application server handling team hinted that this might be happening due to the maximum limit which server can handle for concurrent requests. But they also told me that they have not set any limit. They are using Oracle BEA WEBLOGIC SERVER.
Can anyone here provide me any guidance about exact reason of this behavior. Specially I am concerned with that how server is becoming up again and again without anybody restarting it?