How to Size Your Test Environment

Determining the number and size of load testing machines needed for your setup is largely a matter of experience.

How many machines do I need for my load test? As for the number of machines, a good rule of thumb to start with is: 1 AC machine per 5k target page views per hour.

How much memory should my test machines have? For RAM, we usually reserve 512 MB for the system, plus about 512 MB for the JVM, plus the configured maximum heap size per agent process. So, for 4 agents per machine, each with a 0.5 GB heap size, we would roughly need 0.5 GB + 4 * (0.5 GB + 0.5 GB) = 4.5 GB of RAM.

Was my choice of machines right? Check the agents’ CPU usage in the test report after your load test so you know whether any adjustments are necessary.