Load-testing a web application

How does one go about testing the server-side performance of a web application?

I'm working on a small web application (specifically, it will solely be responding to AJAX requests with database rows). I want to see how it performs under load. However, I开发者_StackOverflow中文版 cannot upload it to an internet host right away. The development environment is, however, part of the local intranet, so I can use as many machines as I want to hammer the development server, presumably using Python in conjunction with urllib2.

My question is, is such an approach really accurate for determining the high-load performance of a server-side script? Is there a better way to do this? Am I missing something here?

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Have you tried a tool like Apache JMeter? http://jmeter.apache.org/