Fortify WebInspect is an aggressive web application analyzer that rigorously inspects your entire website for real and potential security vulnerabilities. This procedure is intrusive to varying degrees. Depending on which Fortify WebInspect scan policy you apply and the options you select, it can affect server and application throughput and efficiency. When using the most aggressive scan policies, Fortify recommends that you first perform this analysis in a controlled environment while monitoring your servers, and adjust your scan configuration based on that experience before proceeding to test live systems.
The attached document is an excerpt from the WebInspect Help Guide highlighting some additional information on preparing your system(s) for an Audit using Fortify WebInspect.