How many threads/users can one Windows client simulate during my load test?

Question

I'm planning to do a load test of our ASP/.NET web application and need to simulate about 600 concurrent users on our system.

Initially we'll just be running the load test tools (probabaly JMETER or WCAT/WAST) from our personal workstations which are Windows 7/32 Bit Dells (Dual Core processors). I was wondering about how many users I can expect to be able to simulate from one client.

If I can easily do 200 users per client, I'll need to identify 2-3 more clients for the test.

I wanted to ask the community based on their experience how many users I should expect per client on a standard windows box.

Any help is appreciated!

Answer 1

This highly depends on the test plan itself and cannot be answered that easily.

If you for example have 500 users that just do one request and then have a waiting timer for five minutes, this should work. If all users constantly do requests without waiting, this will put much more load on your machine.

It depends on the samplers in use. HTTP requests are less costly than SOAP requests for example.

It also depends on the listeners you have active.

For a normal load test I usually have around 100-300 threads active. I would suggest to start with such a number and to monitor the load (CPU, network) on your client to see how much potential there is.

Answer 2

Without more details about the test scenarios and the hardware, it is hard to give specific answers. But our Load Tester product can (usually) handle this level of users pretty easily on a single machine (assuming relatively modern hardware). The testing tool should scale linearly up to a point, so you should be able to get a good estimate by running 50 users through a scenario that is similar to what you expect to test.