Server 2008 Reporting Incorrect Drive Size

[dliddell]

I have the following issue on both Server 2008 and Server 2008 R2 (has not happened on Server 2003 or 2012 yet) VM's where C:\ drive space is not properly seen by the VM until after a reboot. The drive is Thin Provisioned. After a reboot the server properly sees all the drive space again and is fine for a few weeks to a month but then randomly this will happen again. As you can see in the screenshots below Windows Explorer and Disk Management both report the C:\ as only having 795MB remaining but WinDirStat reports there should be 15.8GB. After reboot the full 15.8GB is reported correctly.

Any ideas?

Incorrectly displaying drive space:

WinDirStat's results of the drive scan:

Disk Management View:

[a_p_]

I can't tell you exactly what's consuming the disk space, but I don't think this is just a display issue. I'd use TreeSize to find out what's consuming the disk space. What I would look at (only a guess) is the folder whare Windows stores it's automatic updates (C:\Windows\SoftwareDistribution).

André

[dliddell]

Thanks for the reply but, nothing is actually consuming the space which is the problem. TreeSize also displays the same information as WinDirStat, where there is 15.8GB free but Windows Explorer shows only 795MB of space, that is until I reboot the server and then W.E. displays the correct space information.

[a_p_]

Out of curiosity I searched the web and found False Low Disk Space which may explain this issue.

André

[GaneshNetworks]

Sometimes Windows GUI (Explorer & Disk Mgmt) cheats you. Please try to check the disk usage by running "diskpart" command, which will give you the actual usage details.

[dliddell]

Thanks a.p that sounds similar to my issue but this is Server 2008R2 and Server 2008, not Windows 8. There is no search folders so this isn't exactly what's happening. I'm leaning towards this being a VMware issue as it appears Windows is not being presented with the full allocation of the thin provisioned drive space. Nothing is consuming the space as you can see in the initial screenshots since a reboot fixes and refreshes the drive information to the correct consumed amount.

[dliddell · Accepted solution]

I have finally come to a resolution for this issue. Stopping and restarting the VSS service (Volume Shadow Copy service) instantly brings back all the missing drive space (in my experience this is anywhere between 5-15GB). Hopefully someone else finds this useful.

Thanks again for the help guys.

[Landisgroup]

As a further note to this issue. I was banging my head against the wall on the very same issue on a vm running Exchange 2010 and back pressure kept halting mail delivery. Filesize Explorer, windirstat, and windows was saying that my extended drives of 100GB ea were showing as 39GB used, but the OS showed only 8GB available. This post had me look at the VSS settings on all the drives and I found that the extended drives were set to "no limit" space for the Volume Shadow Copies which uses the volume shadow service to run. I simply checked the "use limit" and went with the default size setting to correct this very impactful problem. The easy way to get to this setting is to open the computer icon, right click on the problem drive, (in my case the E drive), go to properties, shadow copies tab, highlight the e drive again, go to settings, change the setting.....and experience the JOY! I have to imagine that many others have experienced this same issue, good luck.