We measure end user experience using two complementary approaches: synthetic testing, which involves testing a website by simulating visitor requests; and real user monitoring (RUM), which involves watching actual user interactions with the site.
Basic synthetic testing of websites is easy to implement, and there are many free options available to operators of fledgling websites. It should be the first kind of performance and availability monitoring you deploy for any web application. While it can’t give you the granularity and accountability that comes from watching actual users, it offers peace of mind and an understanding of the percentage of time your site is online and how long it takes to retrieve specific pages.
In this chapter, we’ll look at some of the fundamentals of synthetic testing and how to leverage what you already know from your web analytics data to best configure synthetic tests.
The most basic distinction in synthetic testing is between internal tests run behind your own firewall and external tests run from locations around the Internet. While the bulk of this chapter will focus on synthetic testing done outside your data center by a third party, it’s important to understand the basics of internal testing to know what data you already have on hand and don’t need to use testing services for.
Internal tests are those you run within your own data center to ensure all of your machines are ...