News

Identify idle resources with capacity planning

• By Scott Adams
• January 11, 2006

The best capacity planning/performance management software can help IT leaders identify as much as 50 percent of the IT resources sitting idle in their data centers. There are also several capacity planning techniques available, each useful in different situations.

Trending uses simple extrapolation of resource utilization over time. The advantage of this technique is that it does not require sophisticated tools. A spreadsheet will do, but it can be difficult to take into account non-linear behavior buried deep within a multi-tiered system.

Linear trend analysis looks at historical data and projects a linear trend line, applying upper and lower confidence intervals as well as a threshold at which resources will become inadequate. This capacity planning method is a quick sanity check and identifies over-utilized resources, but it does not allow for experimentation with different configurations.

Simulation modeling, a much more sophisticated capacity planning technique than trending, simulates the queuing events that occur during execution. The downside of simulation modeling is that it can be time-consuming to build and run the models.

Analytic modeling calculates how a queuing network will perform. A model is built based on a description of the system. Hypothetical changes can be made to system configuration or business workloads, and the model will predict how the changes will affect performance. Done properly, analytic modeling is a fast and accurate capacity-planning technique.