When diagnosing performance problems with our clients websites, it is not uncommon for the bandwidth to come into question. Very often, the bandwidth chart will show a distinct plateau and it can be difficult to determine if this is cause or effect. This example shows outgoing server bandwidth (green) as the users (blue) ramp up. It could be interpreted as a bandwidth limitation around 8Mbps. In this case it is not – the limitation is elsewhere in the system.
It can be challenging to prove that bandwidth is the problem. If the bandwidth is not reaching the known limits (i.e. what … Continue reading »
Is your load balanced website using more bandwidth under load than a single server would? In a previous article (“Status code 200 didn’t match expected: 304”), we discussed how a website may return full data content back to a client, even when the browser had the resource cached. If you believed that adding an extra server and a load balancer will increase your performance, this can be an unsettling surprise. The problem arises when two web servers are delivering different Entity Tags for the same static resource:
In this example, we have two requests made to the same public URL, … Continue reading »
When Bell Canada began development of an important new customer-facing application, project lead Mr. Roger Bejjani knew he needed to find a web testing tool that would help fine-tune performance throughout the development process and into production. Having used Empirix (purchased by Oracle) and Load Runner (purchased by HP)in the past, he decided to forgo overpriced software and look for a tool that would give him the functionality he needed at a more reasonable price. The main requirement would be load testing HTTP and HTTPS requests, and the software needed to be easy to use during development as well as … Continue reading »
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:
Performance Testing – Any testing that is focused on measuring the performance of a system. This is in contrast to functional testing, which is primarily focused on measuring the correctness of the system. When you use a stopwatch to measure page load times in your browser, you are performance testing.
Load Testing – Performance testing with the goal of measuring the performance of a system … Continue reading »
So you’ve got a shiny new site designed and ready for testing. You may get some questions like: who are your users, and what will they do while on your site? Sometimes questions like these can be answered with analytics, sometimes with educated guessing. However, for those who can’t answer these simple questions, some options still remain. Among those, one option may soon be a reality: monkeys – lots of monkeys.
In the past, deploying monkeys has been somewhat problematic, as it required extensive training to keep them stationary while using a keyboard & mouse while using computer. This limitation may … Continue reading »
This tutorial will show you how you can use performance goals to customize the reports to give you information that is relevant to the individual performance requirements of your system. The goal is to help you learn to draw better conclusions from the data and get more accurate results. You’ll also spend less time poring through the data.
Reaping performance benefits from using persistent connections on your HTTP web server is nothing new. In a recent test of a SSL site, one of our clients enabled persistent connections on their servers as part of a new deployment. The results were quite impressive: for a single user & negligible server utilization, page durations dropped from 12 seconds to only 3.5 seconds. Persistent connections can contribute to much of this duration difference by reducing the amount of time needed establish new connections. The use of SSL makes this feature even more important, as the SSL layer requires additional session negotiation. … Continue reading »
For Lenox, makers of fine china and crystal, e-commerce has been an important aspect of the business for over ten years. When Lynch needed to test the Lenox website user capacity on short notice, Load Tester was the right tool for the job. It offered the features and flexibility to build complex, realistic test cases and identify performance bottlenecks. Read more about their experience.
ProtoTest, provider of consulting services in specialized software quality and test projects, uses Load Tester to help their clients determine how many users their websites can handle. I spoke with Lawrence Nuanez, Senior Consultant, to find out more.
Last time, I talked about why it is ok to start testing early in the development process. I’m going to continue that thought process to discuss load testing without complete performance requirements. This Load Testing 101 article says “If the real end user is going to do work with your application in a totally different way than you test you are as good as with no testing at all.” While there is a nugget of truth hidden in there, it is easy to take away the wrong understanding.
One interpretation of that statement would be that “you must have … Continue reading »