We have a Windows 2008 server core installation that has a 400GB disk attached to it. When viewing the free space of this disk via the command prompt it reports 35GB free. Computer management also reports 35GB free.

When I view this disk as a network share, using the admin share (F$), and select all and take the file size I see 283GB in use on the drive. that would leave 117GB free as opposed to 35GB from the command line.

I have selected show hidden files and system files on the PC opening the share. I would always be inclined to believe Computer management and the DIR command over an SMB share... but i have been asked to find out why there is a discrepancy here. Have you any ideas why the SMB share is not showing an accurate disk space figure?

Any and all help will be appreciated!


I have selected show hidden files and system files on the PC opening the share.

This is not enough. If you the filesystem ACLs do not allow you to have access to the files, then you will not be able to figure out their sizes. So using select-all->properties will not be accurate. If you happen to have your home directories on that volume and you haven't done anything to modify the default permissions then will not have access to the contents of the users home directories.

You might find it useful to actually enable quotas on the server. It does cost a bit in performance, but the quota scanning isn't limited by ACLs.

  • Hi,thanks for the response... By filesystem ACLs are you referring to NTFS permissions? The user who is viewing this disk via a SMB share is an administrator on the server so should be able to see all files on the disk. – GerryEgan Oct 3 '11 at 13:45
  • The administrator account does not automatically have access to everything. Filesystem ACLs can be set to block access from the administrator. Run a tool like accessenum, I bet you will find that you get access denied on some directories. BTW, how much space do your backups take? Surely you are taking a full backup of your data backup periodically? You are using a backup tool that can use the backup operator privilege to bypass ACLs right? – Zoredache Oct 3 '11 at 16:19
  • Zoredache thanks for your help. in the end we narrowed it down to a hyper-v file for which access was denied to all accounts. – GerryEgan Oct 12 '11 at 12:36

Free disk space is wasted disk space. There is no need to have lots of space free because the file system can make space free when it uses it. Any free space you see means the operating system couldn't find anything at all useful to do with that space, not even anything that could possibly have the tiniest benefit. Free space is bad, it isn't helping you. Used space is good, it's doing useful work that benefits you.

Exactly how it's using the disk space for isn't clear from just your question. If I had to guess, I'd go with shadow copies.

  • David, thanks for your reply, I understand that free space is wasted space, the availablility of space is not my concern... What I would like to find is why when I view this disk across a network(as a share), select all files and find out their total size the figure returned for total amount of space consumed is less than when the disk is viewed in Computer Management. Just trying to explain the difference here... I have looked into shadow copes and it appears to be turned off by default in server core. Thanks for the suggestion though! – GerryEgan Sep 29 '11 at 14:50

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