Late yesterday I noticed that the disk space on my 150GB D: partition was being used up rapidly. At the time I assumed that I had just been a bit lax in my housekeeping, however this morning I finally noticed that the disk space was disappearing in GBs every few minutes despite no obvious activity on the PC.
An initial investigation led me to suspect that Defraggler was the culprit, since this can trigger System Restores which eat up disk space. However, having checked my System Restore settings, I noted that System Restore was disabled for the D: drive, leading me to believe this was a deadend.
Next I fired up WinDirStat to try and identify what was using up so much space, however this revealed nothing unexpected – until I paid close attention to actual disk usage: although Windows calculated my totla disk usage of the order of 120GB, WinDirStat had it closer to 30GB! So, something was using about 90GB of disk without showing up in the disk scans. This again seemed to suggest a problem with System Restore, who’s files are not accessible by WinDirStat. Back to Google…
This time I turned up the following page: http://social.technet.microsoft.com/Forums/en-US/itprovistasetup/thread/578fbe25-65a4-4068-8503-bd6ad3ddaa45
Following the vssadmin instructions I discovered the following:
Shadow Copy Storage association
For volume: (C:)\\?\Volume{26f0eaa5-182a-11df-af43-806e6f6e6963}\
Shadow Copy Storage volume: (C:)\\?\Volume{26f0eaa5-182a-11df-af43-806e6f6e6963}\
Used Shadow Copy Storage space: 1.015 GB
Allocated Shadow Copy Storage space: 1.218 GB
Maximum Shadow Copy Storage space: 6.449 GB
Shadow Copy Storage association
For volume: (D:)\\?\Volume{26f0eaa6-182a-11df-af43-806e6f6e6963}\
Shadow Copy Storage volume: (D:)\\?\Volume{26f0eaa6-182a-11df-af43-806e6f6e6963}\
Used Shadow Copy Storage space: 87.576 GB
Allocated Shadow Copy Storage space: 89.996 GB
Maximum Shadow Copy Storage space: UNBOUNDED
A-ha! So, even though System Restore was disabled for the D: drive, it was still happily eating through my disk. Don’t you just love Windows sometimes?
As instructed, I ran the vssadmin Resize ShadowStorage /For=D: /On=D: /MaxSize=10GB command, with the following end result:
Shadow Copy Storage association
For volume: (D:)\\?\Volume{26f0eaa6-182a-11df-af43-806e6f6e6963}\
Shadow Copy Storage volume: (D:)\\?\Volume{26f0eaa6-182a-11df-af43-806e6f6e6963}\
Used Shadow Copy Storage space: 0 B
Allocated Shadow Copy Storage space: 0 B
Maximum Shadow Copy Storage space: 10 GB
That’s more like it!
Now my disk usage is back down to the expected 30GB and all is right with the world.
So, today’s lesson: if your disk space is disappearing for an unknown reason, use vssadmin to check your System Restore settings even if you have System Restore turned off!
