Hardware and performance

I would try out Jmeter and Moodle already has a tool that will make your test course for you along with the test run. I had success with it when load testing my environment and tweaking settings to improve performance. 

https://docs.moodle.org/25/en/JMeter_test_plan_generator

You might want to look at this post I made a while back if your wanting to find out how many concurrent users your environment can support using the jmeter test plan generator. https://moodle.org/mod/forum/discuss.php?d=313489&parent=1255346