How many times have you been frustrated by a site failing at critical points due to excess traffic? Following recent high profile crashes such as Twitter, Bob Dowson, director at Site Confidence, has compiled its five top tips for successful load testing.
Load testing should be central to organisations’ online strategies, particularly for companies that rely on their websites to take online payments and those which can experience significant peaks in traffic.
Ensuring website capacity is at the requisite level can be vital to both bottom line and reputation, so it is essential that load testing is carried out in line with best practice to provide return on investment.
Tip one: plan exactly what you want to achieve
Begin by clearly defining what you want from the load test and the questions you are trying to answer, starting simply and working towards a real world scenario that is relevant to your business. Make sure you give yourself enough time to plan, execute and complete corrective work. The three phases of a load testing project – before, during and after testing – each need a lot of thought and planning.
Load testing requires detailed information about the performance of your infrastructure, content and network. This means the people doing the testing need access to the teams who can access this data. You need to define the extent of their involvement, their responsibilities, and the information you need from them and they need from you.
Tip two: Be brave! Load test your live website
Testing your live website provides the ultimate assurance that it will perform under load. But make sure you understand the impacts of testing on a live site. Will you place orders as part of the test? Can you test your payment gateway? Will real users be affected in any way?
If you do live test, you need to make sure you inform suppliers and third-party content providers, as you will be putting load on their sites as well. And if you can’t test live, you must ascertain how to make the test platform best resemble the live one.
Tip three: Test what’s critical to your customers and your business
Leverage your analytics and highlight the most popular or business critical feature of your site. Ensure you understand what people are going to be doing on your site. Decide which user journeys touch on all parts of your system or infrastructure; how can you be sure that every aspect is tested? Time spent here designing your load test is invaluable.
Tip four: Understand your errors
It sounds like such an obvious point, but it’s often not followed. Don’t just tick a box to say you’ve load tested! Dig into the errors to see where the weaknesses lie. You may need to understand performance in the future when usage patterns change. Understand what your errors are telling you – they will give you a greater understanding of your site.
Tip five: Test and test again
Load testing always highlights vulnerabilities – it is rare that your site will pass first time. Find your system’s weak points, and then look to make improvements there and then. Re-test to ensure you have increased performance as you expected – and repeat the process. Iterative testing leads to more rapid improvement.
Ensure you build in time to discover issues between tests. Also build in time to try out different system configurations (such as compression, persistent connections and caching).
By Bob Dowson
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