Performing a Stress Test on Web Application?

Question

Here's another vote for JMeter.

JMeter is an open-source load testing tool, written in Java. It's capable of testing a number of different server types (for example, web, web services, database, just about anything that uses requests basically).

It does however have a steep learning curve once you start getting to complicated tests, but it's well worth it. You can get up and running very quickly, and depending on what sort of stress-testing you want to do, that might be fine.

Pros:

• Open-Source/Free tool from the Apache project (helps with buy-in)
• Easy to get started with, and easy to use once you grasp the core concepts. (Ie, how to create a request, how to create an assertion, how to work with variables etc).
• Very scalable. I've run tests with 11 machines generating load on the server to the tune of almost a million hits/hour. It was much easier to setup than I was expecting.
• Has an active community and good resources to help you get up and running. Read the tutorials first and play with it for a while.

Cons:

• The UI is written in Swing. (ugh!)
• JMeter works by parsing the response text returned by the server. So if you're looking to validate any sort of javascript behaviours, you're out of luck.
• Learning curve is steep for non-programmers. If you're familiar with regular expressions, you're already ahead of the game.
• There are large numbers of (insert expletive) idiots in the support forum asking stupid questions that could be easily solved if they'd give the documentation even a cursory glance. ('How do I use JMeter to stress-test my Windows GUI' shows up quite frequently).
• Reporting 'out of the box' leaves much to be desired, particularly for larger tests. In the test I mentioned above, I ended up having to write a quick console app to do some of the 'xml-logfile' to 'html' conversions. That was a few years ago though, so it's probable that this would no longer be required.

I've used The Grinder. It's open source, pretty easy to use, and very configurable. It is Java based and uses Jython for the scripts. We ran it against a .NET web application, so don't think it's a Java only tool (by their nature, any web stress tool should not be tied to the platform it uses).

We did some neat stuff with it... we were a web based telecom application, so one cool use I set up was to mimick dialing a number through our web application, then used an auto answer tool we had (which was basically a tutorial app from Microsoft to connect to their RTC LCS server... which is what Microsoft Office Communicator connects to on a local network... then modified to just pick up calls automatically). This then allowed us to use this instead of an expensive telephony tool called The Hammer (or something like that).

Anyways, we also used the tool to see how our application held up under high load, and it was very effective in finding bottlenecks. The tool has built in reporting to show how long requests are taking, but we never used it. The logs can also store all the responses and whatnot, or custom logging.

I highly recommend this tool, very useful for the price... but expect to do some custom setup with it (it has a built in proxy to record a script, but it may need customization for capturing something like sessions... I know I had to customize it to utilize a unique session per thread).

A little late to this party. I agree that Pylot is the best up-and-coming open source tool out there. It's simple to use and is actively worked on by a great guy (Corey Goldberg). As the founder of OpenQA, I'm also happy that Pylot now is listed on our home page and uses some of our infrastructure (namely the forums).

However, I also recently decided that the entire concept of load testing was flawed: emulating HTTP traffic, with applications as complex as they have become, is a pain in the butt. That's why I created the commercial tool BrowserMob. It's an external load testing service that uses Selenium to control real web browsers when playing back load.

The approach obviously requires a ton more hardware than normal load testing techniques, but hardware is actually pretty cheap when you are using cloud computing. And a nice side effect of this is that the scripting is much easier than normal load testing. You don't have to do any advanced regex matching (like JMeter requires) to extract out cookies, .NET session state, Ajax request parameters, etc. Since you're using real browsers, they just do what they are supposed to do.

Sorry to blatantly pitch a commercial product, but hopefully the concept is interesting to some folks and at least gets them thinking about some new ways to deal with load testing when you have access to a bunch of extra hardware!

I've used JMeter. Besides testing the web server you can also test your database backend, messaging services and email servers.

ab, siege, tsung, httperf, Trample, Pylot, request-log-analyzer, perftools