Seth B and I have racked our brains today on why a plain-Jane domain controller (just AD-DS role, no DNS, no DHCP, nothing else with any logging load) had <25% free disk space (16/67GB). The weak-sysadmin-crutch-tool WinDirStat showed us an unfulfilling 15GB of <unknown> files. WinDirStat explaination of <Unknown> space
Ok, run windirstat with an Admin token. Sigh – 14.2GB.
So – it evidently is all in the system+hidden folder ‘System Volume Information’
Enter our friend vssadmin.exe.
Even though Shadow isn’t enabled in the GUI for drive C:, WS2008R2 does allow apps and perhaps service packs? to do a system restore point.
Sure enough – we had two – from Feb and October 2012.
Trying to remove via vssadmin failed with an un-useful message “Error: Snapshots were found, but they were outside of your allowed context. Try removing them with the backup application which created them.”
Ok — just *WHAT* application created them. You know what, I don’t care, I just want my disk space back:
vssadmin resize shadowstorage /on=C: /For=C: /Maxsize=4GB
Ta-da! Both of our shadows removed. Our DC now has 36/67GB free (yes we deleted some other detritus).