Version 15.1 User’s Manual

Capacity Planning
In this section, our goal is to understanding the components of Trend Analysis, including:
Understanding the components of the “What IF” Modeling screen
Understanding the methodology to properly capacity plan
In this section, we will learn how to capacity plan our systems for the future. That is, by learning
the What IF modeling techniques, we can accurately predict future hardware and software
needs.
Capacity Planning Rule #1
Before we begin this chapter, we all have to remember the golden rule of capacity planning. It
is:
Capacity Planning is not an exact science …
But I had a great plan …
That is, even when the most structured capacity planning processes are put into place, sometimes what
was predicted doesn’t come true. In other words, the system you predicted you would need may have
been too big or too small.
For the new capacity planners out there … Welcome to the crazy world of capacity
planning, where the gray hair on your head is not going to be the result of a
bad golf game. Here is an example of what could happen in the real world:
Management gives you the following task. Ensure our current systems will work
with the following business factors:
Business predicted growth 12% a year
To support a strategic new application
You apply the methodology that has worked for years, and the following year,
your predicted system didn’t quite cut it. Why? You find out that:
The new application was bigger than expected
A second application was needed to support the business (that no one told you about)
The company business grew 25%
The company bought another company and its related workload
That’s why capacity planning is not an exact science. As structured as your processes are, sometimes
you’re modeling criteria changes. That’s why the goal of this chapter is to create a Capacity Planning
methodology that will make your jobs easier. The goal is being able to build supporting documentation
for capacity planning projects. If your predictions held true, you’re a genius. If they didn’t, you now
have supporting documentation to show how you came to your conclusions.
In the next section, we will start with understanding the What IF Modeling screen.
Version 15 User Manual Page 148 Oct 2011