Debugging Visual Studio Load Test Rig Problems

I was setting up a Visual Studio Load Test rig for a customer recently and we ran into a handful of problems related to Performance Monitor Counters.  Here are a couple of the problems and their solutions.

Problem #1: You run the load tests on the Load Test rig and you get an error that says “The performance counter category ‘Memory’ cannot be accessed on computer ‘{server name}’ (Access is denied); check that the category and computer names are correct.”

What’s Going Wrong?: There’s an “access is denied” error related to one or more performance counter(s) on one of servers under test.  Since performance counters are collected from the Visual Studio Load Test Controller machine in the load test rig, the service account for the Controller doesn’t have permissions to read the perfmon counter on that machine.

The Fix: Log into the machine (“{server name}”) and add the Load Test Controller to the “Performance Monitor Users” group. 

Problem #2: You run the load tests on the Load Test rig and you get an error that says “The performance counter category ‘Memory’ cannot be accessed on computer ‘{server name}’ (The network path was not found) ; check that the category and computer names are correct.”

What’s Going Wrong?: The load test controller is running into a network problem while trying to collect the performance counter from that machine.  There are two possibilities.  1) The Windows Firewall is blocking the traffic to this machine.  2) This machine is not set up to allow Performance Monitor (perfmon) counters to be read over the network.

The Fix: First, check that the firewall is disabled for the offending server.  (It’s kind of a “brute force” approach but it’s fast.)  Second, verify that the “Remote Registry” service is running.  This is usually enough but I’ve occasionally had to start the “Performance Logs & Alerts” service, too.

I hope this helps.

-Ben

— Need some help load testing your application?  Want some training for Visual Studio Web Performance Tests, Load Tests, and Test Agents/Controllers?  Drop us a line at info@benday.com.