We have a lot of information about load testing in our blog and tutorials, but customers often ask for something more comprehensive to help them get started. This guide gathers some of the best articles and posts — from our own site and others — to cover the most common questions about load testing. The goal is tool-agnostic advice on how to approach load testing and some of the problems you are most likely to run into. It is an evolving document, so please send us your suggestions for topics that should be included.
Load test, performance test, stress test, soak test — there are numerous terms to describe these efforts, and even within the testing community there is no unanimous agreement on them. A few working definitions line up well with the most common usage. Read more.
Before you begin load testing, it is worth spending time to determine exactly what you are trying to accomplish. In general, load testing answers questions like "How many users can our site handle?", "How many transactions per hour will it support?", and "Will it crash when we go live?" Before jumping in, be sure you know which questions you need to answer. Read more.
The system is not done yet. You are still writing code. The final hardware is not in place. None of these are reasons to delay load testing. Read more.
These six questions will help you decide.
In any moderately complex system there are dozens or even hundreds of scenarios that are candidates for load testing. You are not likely to have the time or resources to test them all. Read more.
You should test early, and test often. Read more.
Most load testing tools are built around the concept of simultaneous users. Frequently, the only data available for estimating expected load is not the number of simultaneous users. These calculators help you translate.
Modern web applications frequently include services provided by third-party servers — banner ads and click-tracking services are common examples. In many cases, including these systems in your load tests can significantly degrade the value of the results. Read more.
Using a stepped ramp profile gives you a lot more information from each load test. Read more.
There are many factors to consider when configuring a load test. How quickly should the users ramp? How long should the ramps be? How does this relate to datasets and load engines? Read more.
Review this pre-flight check-list before you start a load test. Some items are specific to our software, but many apply to any load test.
Most systems complex enough to warrant load testing have a database as a critical element. Read why you should have your DBA involved in your load testing.
Maximize the capacity of your load engines by tuning the memory settings.
It is easy to misinterpret various system limitations as a bandwidth or network limitation. This article gives quick tips on using your load testing software to rule one out, and our web bandwidth post explains what web bandwidth is and how to test it.