threshold

Event Type: Information
Event Source: VxSvc_fsys
Event Category: None
Event ID: 804
Date: 4/30/2002
Time: 7:50:12 PM
User: N/A
Computer: ODDIE
Description:
Free disk space has reached warning threshold on volume C:

My Windows 2000 server DC has 9G hard drive SCSI with 2.5G of freespace. I do not understand what is this error means.