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We currently use a product from Microsoft called File Server Resource Manager to enable quotas on shares like HOME.

Users sometimes report that quotas work as expected, but from the client perspective, the assigned quota limit for a user’s share is not displayed correctly. For example, in Windows Explorer, users see the total free disk space of the entire HOME volume instead of the free space remaining under their quota limit.

According to the Program Manager for FSRM, Georgi Matev, the problem is a deficiency in the SMB (CIFS) protocol that causes all free space queries to be done on the root of a share. This means that if the quota is set on the root of the share, then the mapped drive will correctly show the quota aware free space. To illustrate this, consider the following two cases:

Case 1: Quota on the root of a Share

Volume D:\ with 20 GB free space
D:\foo is shared as \\server\foo 
There is a 100 MB hard quota on D:\foo
On the client, \\server\foo maps to O:\. Then the free space reported on O:\ will be 100 MB

Case 2: Quota on subfolder in a Share

Volume D:\ with 20 GB free space 
D:\foo is shared as \\server\foo 
There is a 100 MB hard quota on D:\foo\bar
On the client, \\server\foo\bar maps to O:\. Then the free space reported on O:\ will be 20 GB because SMB directs all free space queries to \\server\foo

We need to enable Case 2 for user HOME folders, so each user can have a different quota.  However,  for Windows XP clients (and for MAC OS X clients), the workaround is to have the quota on the root of the share (like in case 1).  We simply cannot do this for HOME folders.

This has been fixed for SMB 2.0 and will not be a problem when clients running Windows Vista (or newer) access the server shares.  It is unclear if Group Logic will be able to also institute a fix for using AFP (MAC OS X).

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