The Storage Team Blog about file services and storage features in Windows Server, Windows XP, Windows Vista and Windows 7.
This is a common observation among customers using FSRM. They 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 volume instead of the free space remaining under their quota limit.
According to the FSRM Program Manager, 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 spaceD:\foo is shared as \\server\foo There is a 100 MB hard quota on D:\fooOn 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\barOn 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
For Windows XP clients, the workaround is to have the quota on the root of the share (like in case 1). This has been fixed for SMB 2.0 and will not be a problem when clients running Windows Vista access servers running Windows Server "Longhorn."