I was conducting a loadtest on our internal application from with in LAN with no proxy. The test runs fine till around 50 user load and the response time is steady under 1 second. But once user load increases above 50 user range the response time shoots up sharply to above 10 seconds. I repeatedly tried manually using browser and I can see that the application is loading in less than 5 seconds even after clearing up the cache.
The test starts giving lots of "Failed to connect to server "XXX.xxx.x.xxx:xxxx": [10060] Connection timed out" error once I reach around 250 users. The LR response time is around 40 seconds at this point. At the same time I am able to access the application in under 20 seconds using a browser from the test machine and it never fails from a browser. Has anyone else faced this issue? Any ideas on what might be the possible cause for the error?
I did a bit of debugging and identified that connection time is high (almost 60%) in web page diagnostics. This might be the cause of high response time for LR, but what might cause this?