[Lustre-discuss] Per directory quota

[Ken Hornstein]

>Without size-on-mds, either way would have to query both the mds and  
>each OST to get the size info.  Not being that familiar with size-on- 
>mds, it does seem likely that "du" would still have to query the OST  
>for size info, even when "ls -l" does not.

As someone who has spent the past week or two struggling with the
size-on-mds code ... IF everything is working right (a reasonably-sized
IF), then it should not.  AFAIK, "du" is simply calling stat(), which
is the same thing "ls -l" is doing.  Certainly part of the information
you store as part of SOM is the disk block usage, which is what du is
adding up.

--Ken