The Utilization Saturation and Errors (USE) Method is a methodology for analyzing the performance of any system. It directs the construction of a checklist, which for server analysis can be used for quickly identifying resource bottlenecks or errors. It begins by posing questions, and then seeks answers, instead of beginning with given metrics (partial answers) and trying to work backwards.

The USE Method can be summarized as:
For every resource, check utilization, saturation, and errors.

On the same website:

• USE Method: Linux Performance Checklist
• Linux Performance