[performance] Best way to stress test a website

The ab (apache bench) tool allows you to send many requests to a single page and you specify how many clients you want to be used and how many concurrent connection you want.

This may be the first step when developing a site. Just test some pages with a specific load. This way of benchmarking may have some problem, like caching being over used.

Later you may want a tool that simulate some concrete traffic and not for a single page. I don't have a refence handy on such tool yet.