Using jMeter to test IIS web garden - requests are using the same worker thread

Question

I am using an IIS web garden for long running requests with 15 worker processes.

With, for example, 3 browsers, typically multiple worker processes are used.

With Apache jMeter, all requests are using the same worker process.

Is there a way to force the use of multiple worker processes?

Answer 1

This may have at least 2 explanations:

• You have some hard coded ID or session ID in your test plan. Check for their presence and remove them, add Cookie Manager to your test
• You have a load balancer that work in Source IP mode, in this case you need to either change policy to Round Robin or add 2 other machines

If you are using 1 thread with X iterations and expecting different workers then check that:

Cookie Manager is configured this way:

And Thread Group this way (notice "Same User on each iteration is unchecked"):

If issue persists, then please share you plan and check that you don't have somewhere in Header Manager a hardcoded id leading to using 1 worker

Answer 2

Well-behaved JMeter script should produce the same network footprint as the real browser do so if you're observing inconsistencies most probably your JMeter configuration is not matching requests which are being sent by the real browser.

1. Make sure that your JMeter test is doing what it is supposed to be doing by inspecting requests/responses details using View Results Tree listener
2. Use a 3rd-party tool like Wireshark or Fiddler to capture the requests originating from browser/JMeter, detect the differences and amend your JMeter configuration to eliminate them

More information: How to make JMeter behave more like a real browser

In the absolute majority of cases JMeter script is not working as expected due to missing or improperly implemented correlation of the dynamic values