Posts Tagged ‘LoadTest’

"true" client side testing best practices

Written by Ingmar Verheij on June 9th, 2011. Posted in Performance testing

iRobot NS5When performing a LoadTest user actions are simulated. This implicates that mouse or keyboard actions are executed based on a script, based on a scenario, and that the script waits for a response on the screen.

The response on the screen can be determined using API’s giving information about windows present, or the controls on the windows. For instance: the script waits until a window is active with the caption "Microsoft Word".

Another way of determing if a response is given is by comparing the content of the screen with a bitmap. For instance: the script waits until an empty document is displayed in Microsoft Word.

The difference between the two techniques is that a window caption is present right when the application is launched (even if the application is still loading) while the content on the screen is more simular to the way users interact in a session. So looking at a screen region is more accurate, it prevents assumptions (best practice #9 in loadtesting best practices) like "how much time should we wait between lauching an application and clicking on a menu?”.

In this article I will be discussing some best about practices about “true” client side testing (best practice #12 in loadtesting best practices).

Validating design for virtualized branch office server

Written by Ingmar Verheij on May 30th, 2011. Posted in Performance testing

Recently a large system integrater asked me to validate a design they’ve made for a customer. Their customer has around 100 branch offices in europe and requested a new infrastructure that would be managed by the system integrator.

Although the design in general has been validated (the building process was started months ago), the scaling was based on estimates. In fact, there where some assumptions during the design phase. With the deadline coming closer more doubts rised about the scaling.


We agreed on performing a loadtest to simulate the user actions, validate the design and find bottlenecks before the implementation. A nominal load of 100 users was required.

Secondly, the impact of a System Center Configuration Manager (SCCM) deployment on the overall performance was needed. Will there be an impact on the file and print capabilities and how much is that impact?

Loadtesting best practices – Part 2

Written by Ingmar Verheij on May 25th, 2011. Posted in Performance testing

This is the second part in a series two about loadtesting best practices.

The first part focused on the “basics” of loadtesting, most of them where about preparation. You can find the first part here.

In this second part I’ll focus on some more advanced topics which are usefull in a later stage of the process.


Loadtesting best practices – Part 1

Written by Ingmar Verheij on May 23rd, 2011. Posted in Performance testing

Before I start discussing best practices about loadtesting, let me first tell you what my definition of a loadtest is.

“Testing a system with representative load, to determine if the nominal load can be handled”.

This means that if you start loadtesting you need to know the nominal load and have an expectation of the outcome. You will find that most of the best practices has to do with preparation, not with fancy techniques. An different type of test that is frequently called a loadtest, is a stresstest. A stresstest has a different purpose, as can be read in my definition of a stresstest.

“Testing a system above its nominal load, with the purpose of determining if the system in the future can handle a bigger load and to find a bottleneck.”

LoadTest are commonly used to scale an environment. These environments can be a SBC environment like Citrix XenApp or Microsoft RDS, or a VDI environment. But other environments like file, print or webservers can be loadtested aswell. In fact, if you can create the load by simulating user actions, you probably can perform some sort of loadtest.

Now let’s start with the best practices. I’ve written these down in the past years while I was performing loadtests with the DeNamiK LoadGen, the best practices apply to (almost) all loadtesting applications. You can say I learned it the hard way. Although there’s nothing wrong with that, you can learn from my mistakes.

This is the first  part, focussing on the “basics”. Part two will focus on more advanced topics.