If you want to set it up for the atlas or for a custom map, go into the NetCrunch Monitoring Policies window (click 'Policies' button on main program bar). You can also set it up for a node, by right clicking on a node, selecting Alerting->Edit Node Alerting Policy. Then follow these steps:
- click 'Add' button to add an event
- from 'Windows' tab select 'Windows Application Performance Threshold' option
- click on the blue text to find the performance counter
- browse to Performance object "logical disk"
- select %Free Space
- select Instance D: (or other drive)
- click Add and change 'exceeds' to 'drops below' expression
- set up the threshold to 10
- click 'OK' when done
You've just defined the Event - now create the alert, to see the remainder of the steps see related article Configuring an Alerthere.