Using Two or More Load Generators with LoadRunner

LoadRunner is a suite of applications designed specifically for performance testing of computer systems.

Put at a very high level, LoadRunner is used to throw load (or Virtual Users in LoadRunner terms) at a system to check for performance counters such as throughput, CPU per transaction etc. LoadRunner supports a variety of different architectures including Web, ERP, CRM and more.

This article details the steps of how to set-up multiple load generators to work with your LoadRunner Controller environment.

There are several drivers for going with this approach:

• Your load generator may actually sit on the same box as your Controller (design flaw)
• Your load generator may be a low spec box which maxes out at X number of VUsers
• You want load to hit the target from multiple machines to introduce threading.
• etc

Set-up

It’s a pretty straight forward procedure; unfortunately I couldn’t find any decent content on the web to actually guide me through this process or anything that detailed what needed to be done to actually get the load generators set-up.
At first, I thought LoadRunner came equipped with some sort of ‘agent’ that could be deployed to a server and set it self up as a service which would then talk to the Controller; however this did not seem the case and it turned out that the software actually needed to be installed on the target machine.

Requirements

• LoadRunner installer – preferably the same version as any existing versions of LoadRunner you may have installed on other machines

Install

• Launch the setup.exe on the machine you want to set-up as a load generator
• Install with the ‘Custom‘ option – deselect all the options that relate to the Controller (we only want to install as a load-generator so we don’t want any Controller components lingering about)
• After installing, you may be asked for some configuration input, such as your username and password
• On the Controller, click on ‘Scenario’ –> ‘Load Generators…‘
• Here, simply enter the name of the box we just set-up as a load generator.
• Click ‘Connect’

Troubleshooting

• If the Controller cannot connect to the load-generator – check your firewall settings
• Also click the ‘Details…’ button to double check that every thing is in order there

Notes

This was tried and tested on LoadRunner 8 and 8.1. I expect the procedure to be similar on later versions but I cannot guarantee that.