MACROMEDIA COLDFUSION MX-CLUSTERCATS Use Manual page 32

Load-testing considerations
Before starting your load testing, consider the following:
Define benchmarks early — ensure that you understand your website's performance
and scalability requirements before you start running tests against it. Otherwise, you
won't know what you're testing for and the statistics you capture won't have
significance. Also, remember that the benchmarks you define should be customized
for the current application; don't simply reuse benchmarks from an earlier site on
which you may have worked. Each web application is distinct in terms of its design,
construction, back-office integration, and user experience requirements.
Ensure that the test environment mirrors the production environment— create a test
environment that is as close as possible to the production environment in which the
website will be hosted. If you don't simulate a similar network and bandwidth
scenario, or use the same types of servers, or ensure that the same versions of software
(operating system, service packs, web server, and third-party tools) reside on the test
and production servers, you can't anticipate problems nor determine why they occur.
The number of possibilities would be too large.
Minimize distributed environment load testing — load testing in a distributed
environment can be problematic if the network on which you perform load tests
becomes congested, resulting in poor response times. Also, if everyone else in the
organization uses the network for their everyday activities, such as e-mail, source
control, and file management, an increased load on the network will probably cause
significant network degradation for them, and accompanying frustration.
In such a scenario, it might be more effective to physically sit at the server on which
the application resides and perform the tests locally, rather than bring the entire LAN
or WAN to a slow crawl. Also, by testing locally, you can better rule out the network
as the source of the scalability problems. Alternatively, you might be able to configure
a separate subnet on the LAN or WAN that is distinct from the subnet on which
everybody else in your environment uses network services.
You should have a good overview of what scalability implies, the core elements that
compose it, some of the issues that affect successful implementations, and the tasks that
must be performed to verify that your web applications are able to achieve satisfactory
scalability.
The next section describes website availability and reliability concepts and
considerations.
22 Chapter 2 Scalability and Availability Overview