Load Testing Blog
Measuring the Performance Effects of mod_deflate in Apache 2.2
Enabling mod_deflate can reduce the bandwidth usage on a particular file by up to 70%, but also reduces the maximum load a server can handle and may actually reduce site performance if the site compresses large dynamic files. Read the full report for a complete analysis.
Is the last mile relevant to Load Testing?
One of our competitors has recently been emphasizing the use of their monitoring network during load tests. The pitch goes something like this: “With our last-mile monitoring network you can determine how different geographical regions will experience your web pages.” This solution has been implemented by using testing agents in the homes of real consumers to measure performance during a load test.
At first glance, this peaked our interest. However, after some analysis, we started to question the real value of this approach to load testing:
Will this approach dilute the value of the load test results?
Can the same information be obtained … Continue reading »
Load Tester improvement – better success and fail metrics
Previous versions of Load Tester had 2 metrics describing the success or failure of a web page (or single transaction) during a load test: Repeats and Errors. A Repeat was counted any time a valid HTTP response was received from the server. Errors, however, were a bit more complex. Errors could occur at any point in the transaction, from establishing a connection to post-response validation. An error was counted if the connection was terminated in the middle of a transaction. It was also counted if the status code from the server indicated a failure (e.g. a 500 status). Validators record … Continue reading »
New Load Tester feature – web page performance goals
Load Tester has supported the concept of a performance goal for quite a while, but the implementation has been rather limited. We have completed work on an improved version for our next release (3.6). Load Tester now provides the ability to set a performance goal for each web page and/or transaction in a testcase individually. Of course, you can still specify a global page performance goal, as you could in the past. In addition, users can specify a default page (or transaction) duration goal for an entire testcase and then override that value for each page or transaction. The performance … Continue reading »
Load Engine simulates 3500 users on a single PC in performance test
We are frequently asked how many load engines will be needed to run a load test. Some general guidelines are provided here. Those guidelines were established using a fairly typical test scenario. With some tuning, we were able to tune the OS and Load Engine to simulate 3500 users on a single computer.
Memory consumption and reclamation – Chrome vs. Firefox
I reboot my laptop as infrequently as possible – which means that I keep Firefox running for weeks without restarting. At least, I would prefer to. But the longer it runs, the more memory it gobbles. The only way to reclaim it is to restart.
So when I read about the tab-isolation feature in Googles new Chrome browser which uses a separate process for each tab, it peaked my interest. I installed Chrome and tried a very quick (and not very scientific) test, as described below.
Firefox had been open for a few days and currently had 8 tabs open. I am … Continue reading »
How many users should I load test my system with?
When customers are preparing to buy our load testing software, they frequently ask “How many users should I load test my system with?”. Naturally, we can’t answer that question without a lot more information about the performance requirements and the expected usage of the web application.
Load Testing a cluster of web servers
Ok – so you’ve spent months putting together a shiny new mission-critical web application, complete with multiple web servers, a few application and/or database servers. There is a load balancer in the mix or maybe you are using Microsoft NLB (Network Load Balancing). The system is nearly ready to deploy and it is time to run a load test. The first inclination is to fire up the load testing tool and throw the maximum expected load at the entire cluster. After all, there is no sense in wasting time with the smaller pieces, right? Wrong.
Load Test Configuration – using a stepped ramp
One of the most common load testing mistakes made by beginners is their configuration of the user ramp rate. This is best illustrated with an example configuration that we see frequently.
Load Testing .NET Applications
Introduction
Load testing is one of those steps that should be performed for every major system rollout but rarely happens. In this article, we will demonstrate the basic procedure for load testing web-based applications, using an ASP.NET application as an example.
Why Load Test .NET?
Working for a performance tools company, I have the opportunity to assist many companies with their load testing efforts. A large number of these efforts happen immediately before deployment or shortly after deployment, when live usage has determined that performance is inadequate. Naturally, performing the load testing at this stage in the project is much more costly than … Continue reading »