Don't Crash in Holiday Traffic

The following article about load testing is from Patrick Lightbody at Neustar.

"The good news for e-commerce retailers: Industry sources are predicting a successful 2011 holiday season. Though the economy is still fragile, eMarketer predicts that sales will match or surpass 2010 levels, with an estimated growth of 12%. Strong first-half online sales have provided nice momentum, with price-conscious consumers using the Web to compare and find the best deals.

Now the bad news: Every so often you hear about a retail site crashing — a victim of its own success — unable to handle higher traffic generated by an exclusive deal with a hot clothing line or highly anticipated product. While these tales are hardly exclusive to the holiday season, the increased traffic during the holidays means it's unquestionably the worst time for a storefront outage. In many cases, disaster isn't inevitable. There's a way to prepare your website and be ready for marketing driven events, or more pressingly, with Black Friday, Cyber Monday and all the days of Christmas.

Yes Virginia, it's that time of year for load tests.

Find Bottlenecks and Overall Site Capacity

For the uninitiated, load testing is the practice of generating heavy traffic loads to see how a website or application performs. A thorough load test will identify bottlenecks both inside and outside your firewall (more about this in a moment) and lets you know how many simultaneous users you can serve. In the end, you'll know what works, what doesn't and how to prepare for your next traffic surge. For online retailers, load testing should become a holiday tradition.

Give Yourself Enough Time

How does it work? Typically, you run a series of at least three tests:

• The first test provides you with a snapshot of your site's current performance. This will always yield areas of improvement.
• The second test validates all the changes made after the first test and identifies any remaining bottlenecks. You'll probably make additional tweaks.
• The third test is your application's final pre-launch validation. Ideally, you'll uncover its peak performance point.

You'll need at least two to three weeks to accomplish all of this. Give yourself a month and you'll be in solid shape.

Browsers: Go with the Real Thing

Thanks to cloud computing, it's now cost-effective to load test a website using real browsers. Real browsers let you create more life-like site traffic, unlike virtual browsers that simply mimic a browser's http request/response sequence. This is especially true when testing rich media like Flash banners or videos. You'll come away with a clearer view of your end user's experience.

Test Beyond the Firewall, Too

The most frequently visited parts of your site are the most important to test: applications supporting your home page, browsing, product selection, checkout and exit. While some applications are found inside your firewall, many (easily 50%) live beyond it. Whether you run your own tests or use a vendor, be sure to include external testing. Without it, you're only getting half the picture.

Outside Help

In working with load testing providers, you basically have two choices. One, on-demand services that let you run tests 24/7 and two, full-service testing, which normally includes a dedicated engineer. If you have the resources on staff, on-demand is a good bet. Besides giving you greater flexibility, it usually costs less. Tip: See if you can get started with a free trial.

If you don't have the expertise on staff, or your environment is more challenging, you might opt for full-service testing. With an experienced engineer to manage the engagement and provide professional analysis and recommendations, you'll be more confident about your tests.

Besides yielding a wealth of information, load testing can help you sleep bett
er. During the holiday rush, that's the best gift of all.

Patrick Lightbody is senior director of product management at Neustar."

A good article on load testing.