Well it really depends on your application you are testing and how much memory firefox takes in memory when you use the application plus a little bit extra for the HP interface code. Remember TruClient basically is QTP Light working directly in a browser DOM. So each virtual user is a little bit more weight memory wise as have X full firefox instances open at the same time and not sharing processes. To be honest with our older Xeons (2.8ghz quad core), and 3 Gig memory we are getting about 9 to 10 truclient vusers per machine. We only use it when absolutely necessary. I've heard claims of 100 per machine, but I can't get anywhere close to that AND have reliable transaction response times between tests.
Petar, thanks ! I understand the application dependancy in memory usage. So in front of using ajax true client for a test we need to define some kind of test ourselves to have info on memory usage per virtual user for every different application under test.
Yeah, pretty much that's the case. We usually try to no push memory on the injectors >80% and cpu >60% especially in VM's since all sorts of unpredictable results start creeping in. If you have the opportunity to smoke test your scripts/env I would recommend running say 5 vusers for a few mins and gather injector data on how much memory is in use then extrapolate from there. I've found there is no magic solid number so a bit of experimentation is in order.
