Load Testing Blog
Tips for Successfully Testing from the Cloud
With Load Tester 4, we’ve made it easy to harness Amazon’s power for Load Engines quickly and inexpensively. Once you’ve familiarized yourself with the basics, here are a few rules of thumb:
1. Get to know the Amazon EC2 Console . The console will quickly tell you what instances you have running – and subsequently what you are getting billed for.
Note that the console shows you only data for a selected region, so you should check each region separately. Load Tester will automatically prompt you after a test and before shutting down Load Tester if you have running engines … Continue reading »
Load Testing: Software or Services?
One of the common questions our customers ask is: “should we buy software and do the load testing ourselves or hire someone to do it?”.
The question is one with few easy answers, but in this blog entry I’ll lead you through the thought process so you can decide which option is the best for your situation.
The first question to ask is how often do you need to do load testing? If you’re planning on testing more than twice a year its usually cost effective to purchase software and learn how to use it. This is true of … Continue reading »
Keeping Your Load Testing Cases Current (How To)
Maybe you’ve just finished your first crack at testing, handed some results up to the development team, and are just got a note that the dev team has revamped the site in preparation for the next test. Or maybe you completed testing last month and are ready to retest the site against any regressions. Are all the testcases setup from the last round of testing still going to work? Are you going to have to create all new testcases? Here are a few quick ways to find out:
1. Run a replay with your existing testcases. If the replay fails … Continue reading »
Introduction to Load Testing: Part One
The website is completed or mostly completed and you have been advised to do a load test, but you are not quite sure were to begin. First things first, a basic understanding of load testing procedure is needed. The load testing procedure mostly involves understanding the web-application that will be tested. Understanding the applications refers to many different factors such as:
Understanding the functionality of the website.
Understanding the general network layout.
Understanding the software and hardware used by the system.
These factors are useful for a number of reasons, not only do they make the load testing process easier, but they can help … Continue reading »
Load Testing Back to Basics: TCP Connection Failures
Load Tester is a web site load testing tool, and as such we deal primarily with the most popular Internet communications protocol: the Hypertext Transfer Protocol, or HTTP, which controls the request and transmission of web pages between browser clients and web servers. HTTP is based on a lower-level protocol known as the Transmission Control Protocol, or TCP. For the most part, TCP works in the background, but its proper function is critical to your website, and problems at the TCP level can show up in many different ways during a load test. … Continue reading »
Faster Websites Are More Profitable
An experiment by a vendor of website accelerator appliances showed that optimization of website performance had a measurable improvement on visitor retention. Visitors to the optimized site:
had a 1% lower bounce rate
visited 4.5 more pages
spent 27% more time on the site
For the retail site they tested, the impact was felt on the bottom line:
conversion rate increased 16%
order value increased 5.5%
For details, read the full article: Proof that speeding up websites improves online business.
Chris, Chief Engineer
Simulated DNS Load Balancing Improves Testing Accuracy
With the release of Load Tester 4.1, we’ve been discussing some of the new features available in this release. One of those features is Simulated DNS Load Balancing. This feature offers improved testing accuracy over previous versions of Load Tester.
This feature is designed for systems which may use DNS to alias a single hostname to many different IP addresses, allowing the DNS system to provide load balancing. This works effectively when the users or load engines greatly outnumber the number of servers, and are well distributed and not in a common location. For users that wish to test their system … Continue reading »
What is “Web Bandwidth” and how do you test it?
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 »
Load Testing tips for Database Administrators
Nearly every useful web application is backed by some sort of database – usually a relational database. Many database administrators (DBAs) have never participated in a load-testing campaign and are sometimes even considered tangential to the load testing process.
However, your DBA is a crucial part of the load-testing team. In addition to the obvious skills of database performance analysis and tuning, the DBA brings other advantages to the project:
insight into how the application interacts with the database that may not be obvious from the perspective of other team members
ability to quickly backup and restore various database snapshots to increase consistency … Continue reading »
Is your Load Balancer increasing your Bandwidth usage?
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 »