I have two OS X Server 10.4.9 file servers that are currently
running AFP and SMB. We have for the past couple of years been
successfully enforcing disk quotas on our AFP users. However, we
have not been able to enforce quotas on our SMB users. Over the
past week I have had the time to trouble shoot this issue more and
upon discussing this with Apple tech support I was told that there
is a bug in SMB quotas and they are not functional as of 10.4.x.
Later this week I spoke with another engineer outside of Apple and
was told flat out that OS X Server does not support quotas on
anything but AFP.
Disk quotas are supported on SMB.
I verified this myself by creating a test user and trying to copy a
file that exceeded the quota to that user's home directory. While
AFP did not allow the copy to take place, SMB, FTP, and even SSH all
allow that file to be copied to that user's home directory.