Load test fails after 400vusers login.

Hi All,

We are doing a load test with 500 vusers(with 20 ids logged in concurrently),after 400 vusers login,we noticed below error

Found  error “Action.c(10): Error -27796: Failed to connect to server "xxxxxxxxxx.com:8080": [10061] Connection refused” and timeout issues

We  implemented tomcat cofigurations

such as

maxThreads=600 on each node(4x600=2400 threads)

connectionTimeout=0

Initial memory pool and max memory pool to 1024

XX:MaxPermSize=256M

-XX:PermSize=256m

-XX:NewSize=171m

-XX:MaxNewSize=171m

-XX:SurvivorRatio=2

-XX:TargetSurvivorRatio=90

-XX:+DisableExplicitGC -XX:+UseTLAB

Now,it throws error i.e status-code=500(Internal server error) which found in loadrunner

But still, we can't pass 500 vusers test.

Any suggestion?

Environment:

=========

win2008

BOXI3.1 Sp5 FP4(4 node cluster with 4 tomcats)

tomcat55

Loadbalancer