You have to keep an eye on things like disk space. Schedule this script and have the results for every Domain Controller in your forest emailed to you.
You will need to have the PowerShell Active Directory Module installed (Windows 7 or Server 2008 R2).
The script is attached.
This is what the results look like:
Keep in mind that the limits set in this script are pretty low. If it triggers a “Low” warning you’re in trouble!
You’ll also notice that in the example output above that NTDS, SYSVOL, and OS are all on the C:. Don’t do that! Move NTDS and SYSVOL to separate volumes.