Chapter 14. Load Testing

Once you have diagnosed performance issues in your website and made changes to resolve them, you will need to make sure that the improvements you made really improve performance. If those changes were on the web server or the database server, you will need to load test your changes, for which you need a load testing environment.

Additionally, it is a good practice to load test your website as part of acceptance testing of a new release, just to make sure it can still handle the expected loads. And if your marketing department is planning a campaign that will increase the load on your site, you’ll want to make sure it can handle the expected load. This is not purely a performance issue; some bugs become apparent only under load, such as bugs triggered by low memory conditions.

A load testing environment simply consists of one or more machines hosting the site under test, plus one or more machines that generate a load by simulating visits by many virtual clients.

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