As stated earlier, a great deal of system administration revolves
around resources and their efficient use. By balancing various resources
against the people and programs that use those resources, you waste less
money and make your users as happy as possible. However, this leaves two
questions:
How is it possible to know what resources are being used (and to what
extent)?
The purpose of this chapter is to enable you to answer these questions
by helping you to learn more about resources and how they can be
monitored.
Before you can monitor resources, you first have to know what
resources there are to monitor. All systems have the following
resources available:
CPU power
Bandwidth
Memory
Storage
These resources are covered in more depth in the following
chapters. However, for the time being all you need to keep in mind is
that these resources have a direct impact on system performance, and
therefore, on your users' productivity and happiness.
At its simplest, resource monitoring is nothing more than obtaining
information concerning the utilization of one or more system
resources.
However, it is rarely this simple. First, one must take into
account the resources to be monitored. Then it is necessary to examine
each system to be monitored, paying particular attention to each
system's situation.
The systems you monitor fall into one of two categories:
The system is currently experiencing performance problems at
least part of the time and you would like to improve its
performance.
The system is currently running well and you would like it to
stay that way.
The first category means you should monitor resources from a system
performance perspective, while the second category means you should
monitor system resources from a capacity planning perspective.
Because each perspective has its own unique requirements, the
following sections explore each category in more depth.
