Monitoring system capacity is done as part of an ongoing
capacity planning program. Capacity planning uses long-term
resource monitoring to determine rates of change in the utilization
of system resources. Once these rates of change are known, it
becomes possible to conduct more accurate long-term planning
regarding the procurement of additional resources.
Monitoring done for capacity planning purposes is different from
performance monitoring in two ways:
The reason for these differences stems from the goals of a
capacity planning program. Capacity planning requires a "big
picture" viewpoint; short-term or anomalous resource usage is of
little concern. Instead, data is collected over a period of time,
making it possible to categorize resource utilization in terms of
changes in workload. In more narrowly-defined environments, (where
only one application is run, for example) it is possible to model
the application's impact on system resources. This can be done with
sufficient accuracy to make it possible to determine, for example,
the impact of five more customer service representatives running
the customer service application during the busiest time of the
day.