Load Testing Blog
Testing Auto-Scaling Servers with Load Tester 5.1
One of the easiest ways to create a system that keeps up with sudden increases in demand is to use auto-scaling systems offered by many cloud providers. The concept of bringing new systems online to handle demand is nothing new: this has also been used by CDNs for years to replicate high demand data to edge locations. Testing this type of system, however, can become more challenging when the auto-scaling relies on updating DNS records in order to route new users to new servers.
In Load Tester 5.0 and earlier, Load Tester could be set to 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 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 »
Load Test development using proxy servers improved for Load Tester 4.3
Proxy servers are nothing new to corporate users, and Load Tester has supported test development through a proxy server for those testers that were required to use one. However, we’re excited to introduce two new improvements to Load Tester’s proxy support for Load Tester 4.3: more detailed recordings and replays of proxy traffic, and support for proxy authentication.
In all versions of Load Tester, it is possible to change the proxy configuration, and then play an existing testcase correctly using the new proxy settings. Since proxies may require the use of additional HTTP messages to create a tunnel and / or … Continue reading »
Enhanced Integrated Windows Authentication Support in Load Tester 4.2
Load Tester 4.2 offers a substantial number of enhancements over the 4.1 release. One of the last features, which was not available in the 4.2 beta cycle, is completely redesigned support for Connection Authentication Negotiation. For IIS users, just think of “Connection Authentication Negotiation” as support for IIS’ “Integrated Windows Authentication”. Load Tester’s CAN support is a bit more abstract to encompass other servers as well. In fact, the term “Connection Authentication Negotiation” is used to provide support for negotiation of an authentication scheme at the HTTP layer, which may be used to authenticate the browser’s connection to the … Continue reading »
Load Tester 4.2 Preview: Concatenating Values
The next release of Load Tester 4.2 offers a wealth of testcase configuration options, in order to allow users to configure more sophisticated testcases. In this example, let’s take a look at how Load Tester 4.2 can allow you to customize fields by concatenating values.
Take a simple example: you are provided with a list of users in a dataset format with two columns: First Name and Last Name.
In your testcase however, the format is different, and instead the user name is POSTed as a single field in the format “Lastname, Firstname”.
Load Tester 4.2 makes this easy with a new, powerful … Continue reading »
IE Performance Tip: avoid repeating <img> tags
This tip is more for those users who have developed a sophisticated data-crunching interface to their app. On one screen, for simplicity, the app gives a long list of data, without pagination controls being created by the user (such as a “View All” feature). To keep it pretty, each line has a visual icon or some surrounding images. Sound familiar? For example, let’s say the list is created by a testing system, indicating which tests were passed and which failed. The list may look something like:
For this example, we’ve created a few lengthy files to measure IE’s rendering performance. They … Continue reading »
AIX Monitoring Support on the Horizon
We’ve got a lot of new exciting progress making it’s way into Load Tester 4.2. Among these features, Load Tester 4.2 will be introducing an Advanced Server Analysis™ module designed for AIX servers. Like our other Advanced Server Analysis™ agents, the AIX module is capable of running offline, and will continue to collect data about your server even when normal connectivity to the server has been overloaded (unlike some of our competitors solutions). The monitoring agent can collect vital information from your server, including:
CPU
Memory
Disk activity (reads / writes / % utilization)
Network activity (bandwidth in & … Continue reading »
Fixing: Unable to Establish Connection to the server
In this example case, we ran into a situation where a load engine could not resolve the hostname of the server being tested, even though Load Tester was able to record & replay against the server without any difficulty. This problem appears immediately, but only when running a Load Test with the troubled load engine. By using the Engines View in Load Tester, we were able to select and use each Load Engine separately in a Load Test, until the faulty engine had been isolated (this sort of problem will show errors coming back from the engine within seconds, and … Continue reading »
Knowing your Security with Stress Testing
In the past, we’ve had plenty of discussion on how performance effects user experience, and how that relates to conversions. But, can a server’s performance effect it’s security?
During a previous test, we had a customer whose site included a contact form. The user would complete the contact form in their browser, and the application server would convert this response into an e-mail and send it through a mail server. The contact form, coupled with the use of a CAPTCHA, helps to cut back on undesirable messages. During our testing, we discovered that the mail server was becoming overloaded (at only … Continue reading »