If traffic to your website suddenly explodes, what happens to the user experience? You can’t know until you perform load testing. As defined by Wikipedia, load testing involves deliberately demanding more of your website to “determine [the] system’s behavior under both normal and anticipated peak load conditions.”
Accuracy is essential when figuring out how many users your site can handle at one time and identifying where performance suffers as loads increase. Follow these ten tips to set up and execute precise load tests and collect data you can use to improve the onsite experience for end users.
Test with Real Browsers
Some tools available for load testing use virtual browsers, and although it’s possible to get usable results in these simulated environments, you’re better off doing your tests in the browsers your site visitors actually use. This information is readily available on the platform through which you monitor site statistics, and using a load testing tool like LoadView can help you test with a variety of real mobile and desktop browsers. Determine the most popular browsers, and make these the main programs your use for testing.
Know Your Baseline
The length of time it takes a page to load when it’s being accessed by a single user is the baseline number against which to measure other performance data from your load tests. Use a tool designed to record page load times only after every element on the page has been fully rendered, and compare these times to your own manual tests. Since test results will differ, you’ll need to repeat the process a few times to get an average on which you can rely.
Use Your Analytics
Website analytics offer invaluable data for load testing, including measurements of peak traffic in the recent past. Take a look at your busiest days, and note the highest number of visitors your site had at these times. Add 10 to 50 percent to these numbers so that you can simulate extreme conditions when testing. Increasing the expected peak traffic allows you to see how your site would perform should traffic exceed predictions at any time.
Determine Key Metrics
What should you look for when determining the load your site can handle? User experience is at the heart of this type of testing, so the metrics you measure should focus on ensuring a smooth experience even when the site is under stress.
Look at average response times, peak response times and error rates for all pages. Putting these together creates a clear picture of what an actual user would encounter when site traffic is heavy. You should also take note of CPU and memory use to see what peak traffic demands from the systems supporting your site.
Plan with Your Team
Load testing is a bigger job than one person can handle. Meet with your IT team, web developers and anyone else involved in working on your site to create a plan for handling the tests. If everyone isn’t on the same page regarding which tools and browsers to use, the timing of the tests and the chosen metrics, you’ll wind up with useless results.
Include a Deliberate Crash
Finding out what it takes to push your website’s system into a state of failure may seem like an extreme goal for a load test, but it’s helpful to know the absolute upper limit of what the site can handle. Gradually increase the load as you test until the site gives out, noting what happens to page load times and the types of errors you receive. Even if you never expect to have enough traffic to crash the site, pushing the envelope reveals points of weakness and potential errors you may not discover when testing lower traffic levels.
Time Tests Right
The best time to conduct load testing is when users aren’t likely to be visiting your site. Just as you looked at analytics for peak traffic times, you want to determine the hours of lowest activity and schedule your tests during these windows. Taking this approach ensures the network environment doesn’t skew test results and your tests don’t interfere with the experience active users have on the site.
Use a Performance Environment
Testing in a simulated environment instead of a duplicate of your site’s performance environment or on the site itself is a recipe for inaccuracy. To get reliable results, you need to see the real errors users might experience and identify performance bottlenecks on your actual site. A test environment may lack elements necessary to understand how the site really behaves when traffic spikes.
Conducting tests correctly in real browsers on your actual site should yield the most accurate results possible, but the feedback you get is only helpful if you make sure to capture the data. This is why it’s important to ensure your team knows what metrics you’re testing for and how these measure up to your baseline for performance. Compare results from team members, and use the numbers to identify areas on which to focus efforts for improvement.
Test Again and Again
Load testing isn’t a one-time deal. After your initial tests, it’s time to make changes in the areas where performance clearly suffered with the goal of minimizing errors and improving page load times. Once this has been done, repeat the testing using the same browsers, metrics, timing and environment. Weigh your new results against the initial outcomes to see if the changes helped and where new tweaks need to be made to further reduce the risk of problems for end users.
Better site performance makes for a happier audience, and this should be your main goal when load testing. Even the slightest delay in page load times or a single error during an e-commerce transaction can cause you to lose customers to the competition and damage your brand image. Conduct regular load testing to ensure performance remains favorable and your site environment can handle the levels of traffic you expect.