Take the following steps for each agent system that you would like to exclude file systems from: Browse to the element using My Infrastructure.
Under the element's Info sub-tab, click Info & Rescan and then Edit Performance Monitor in the main panel.
Use the Worst Disk Usage Exclusion and Inclusion fields to eliminate (or specifically add) file systems to be included in the Worst Disk Used column of the GlobalScan page for this element.
Click Save.
After completing this process, review the GlobalScan page to verify the changes. Note that the values will not be updated until the next time the agent is polled for performance data.