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.
