A Practical Guide to Load Testing
We have a lot of great information about load testing in our blog and tutorials,
but we are often asked by our customers for something more
comprehensive to help them get started - a book or guide to load
testing. The Performance
Testing Guidance for Web Applications book
is probably the best book currently
available. In our opinion, though, it focuses a bit too much on the
process of getting things done in just the right way and not enough on
getting results quickly. The book is definitely worth
a read, but if you need results in days instead of weeks, it may not be
what you're looking for. In addition, there is a myriad of essential
topics it doesn't address at all.This guide gathers some of the best articles and blog entries, from both our own website and others, to cover the most common questions about load testing. The goal is to provide tool-agnostic advice on how to approach load testing and some of the most common problems. This guide is an evolving document and may never be "done" - so please send us your suggestions for topics that should be included here.
Getting Started in Load Testing
What is Load Testing?
Load test, performance test, stress test, soak test...there are numerous of terms to describe these efforts and even within the testing community there is not unanimous agreement. These definitions line up well with the most common usages. read more...
Why Do We Load Test?
Before you begin load testing, it is valuable to spend time determining exactly what you are trying to accomplish. In general, load testing tries to answer questions like "How many users our site can handle?" How many transactions / hour will it support?" "Will it crash when we go live?". Before jumping in, be sure you know what questions you should be answering. read more...
When is the System Ready to Test?
The system is not done yet. We're still writing code. The final hardware is not in place. None of these are excuses to delay load testing. read more...
Should We Out-source Load Testing or Do It Ourselves?
These 6 questions will help you decide.
Building a Load Test
What Should I Test?
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...
My Test Requirements Are Not Complete. Can I Test?
You should test early, and test often! read more...
How Many Users Should I Test?
Most load testing tools are built around the concept of simultaneous users. Frequently, the only data available for estimating the expected load is not the number simultaneous users. Here are a few calculators to help you translate.
Which Servers Should Be Included in the Test?
Modern web applications are frequently include services provided by 3rd-party servers. Banner ads and click-tracking services are some common examples. In many cases, including these systems in your load tests can significantly degrade the value of the results. read more...
Why Should I Run Ramping Load Tests?
Using a stepped ramp profile in a load test gives you a lot more information from each load test. read more...
How User Ramping Works
There are a lot of 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...
Preparing the Test Environment
Am I Ready To Run, Yet?
Review this pre-flight check-list before you start a load test. Some of them are specific to our software, but many will apply to any load-test.
Overriding Host Names
See how to synchronize a local hosts file with all your load engines automatically.
Get Your DBA involved!
Most systems that are complex enough to warrant load testing have a database as an critical element in the system. Read why you should have your DBA involved in your load testing.
Tuning Load Engine Memory Usage
Maximize the capacity of your load engines by tuning the memory settings.
Interpreting Test Results
Am I Bandwidth-Limited?
It is very easy to mis-interpret various system limitations as a
bandwith or network limitation. This
article gives some quick tips on using your load testing software
to quickly rule out a bandwidth limitation. Our Web
Bandwidth post talks about what web
bandwidth is and how to use our wizard to quickly test it.