Load Testing Blog
Site outage report for 27-28 October, 2011
As many of our customers have noticed, the Web Performance website was unavailable for most of the day on Thursday, October 27th. Much of the site was functional mid-day on Friday, but the support system remained inaccessible throughout the day.
Over the weekend all functionality has been restored and we believe that no data has been lost. However, if you have not received a response to any inquiries via e-mail, our contact form, or our support system, please contact us again so that we may both answer your inquiry and investigate the data loss.
Earlier in the week we experienced a hard … Continue reading »
Identify Performance Goals Early…and Measure Them!
When a load test is complete, you will be asked “How did we do?” Do you know how will you answer that question? Our customers come to us and know, for example, that they need their site to handle 1000 users, but they frequently cannot tell us what “handle 1000 users” means to them. You will need to know which metrics are important and what the goals for those metrics are – preferably long before you start testing.
The first step is to determine what you should be measuring. For websites, you will typically be interested in page duration – how long it … Continue reading »
Content Delivery Networks
When our customers have bandwidth limitations or latency issues, we often encourage them to use a Content Delivery Network. A Content Delivery Network can offer a variety of benefits. What is a Content Delivery Network and what are the pros and cons of using one?
A Content Delivery Network is a cluster of web servers located in different parts … Continue reading »
Internet Explorer Static File Caching Defect
In going through cases we have with some customers, we’ve seen a few instances where Internet Explorer does not cache shared static resources. Within Load Tester, this problem becomes immediately apparent:
Note that the shared CSS, Javascript, and images are re-requested again on the About page and every other recorded page that uses them. Note also, these files don’t come back with a 304 (Not Modified), but instead the full content of the file is sent over and over again through a HTTP 200. Normally, the browser should load these files once, and not need to request them again within the … Continue reading »
Load Test Early!
Customers occasionally ask us “How early should we begin load testing?”
The answer is to test something, anything, as soon as the architecture is available. Performance problems have a wide variety of causes – from a single line of code to a load balancer setup; from a database schema to a server config file. Early in the development of the software you can catch simple coding problems and fundamental architectural limitations that are much easier to fix before a lot of code has been written.
Now, a word of caution: Testing against a scaled-down development or … Continue reading »
Performance Starts with the Developers
Performance starts with the developers as well as the server and network administrators. High-capacity websites do not happen by accident. To perform well and scale big, the system must be designed, built and configured for performance. That means it must be coded and configured with performance in mind, right from the start. Make sure the developer and admins all understand the levels to which the system must perform. Don’t make them guess what “it has to be fast” means.
Two of the most important tasks the test and project management teams to can do to help:
Identify the performance goals for the … Continue reading »
Load Tester 4.3 Released!
Following closely on the heels of the previous release, the 4.3 release focuses on network compatibility and testcase configuration improvements based on feedback from customers and from our services work in the past year with such clients as the US Census and the New York Marathon.
JSON and custom parsers
JSON support – Load Tester now understands the JSON data format which is popular in AJAX apps. A new parser allows the fields view to display the fields within JSON data structures and new detection rules will automatically configure many JSON-related fields.
Parser customization: Load tester now allows selection of which parser to … Continue reading »
Load Tester 4.3 Improvements: Speculative Authentication for IE8 and IE9
Load Tester 4.3 carries a number of improvements for both ease of configuration, and accuracy of test simulation. Among these improvements comes support for speculative authentication, allowing Load Tester to simulate behavior from IE 9. The speculative authentication is only used for HTTP authentication schemes used by Load Tester’s Connection Negotiation Authentication feature. More information about HTTP authentication is available under How HTTP Authentication works and why load testers should care.
To describe the speculative authentication feature, it is easiest to simply look at a testcase using Basic Authentication.
Continue reading »
Deleting Recorded URLs in Load Tester 4.2
Sometimes while recording a testcase, you might capture URLs (like google analytics and certain 3rd party content) that you do not necessarily want to load test. In previous versions of Load Tester, removing any unwanted URLs required selecting the unwanted link and deleting each link individually. Removing the links could be cumbersome and time consuming especially if the unwanted URLs were repeated multiple times on different pages. With the 4.2 release of Load Tester, the Mass Delete function can now be used to delete multiple URLs with the same domain name at the same time.
Note: Recording unwanted URLs can be … Continue reading »
Cloud Load Testing Generator Now $1/hour
There’s no doubt that generating load from anyplace in the world at just the push of a button is one of the cloud’s killer applications. Since we first released the ability to generate load from the cloud back in late 2009 people have logged over 33,000 hours of remote load testing from the cloud. And not a crippled cheapo service, either, but full blown, enterprise quality testing with expert technical support backed by a professional services team.
I still get a kick out of running load tests from the cloud, specifically watching Amazon’s EC2 spin up dozens of computers and … Continue reading »