[Lustre-devel] Lustre HSM HLD draft

[Andreas Dilger]

On Feb 12, 2008  16:25 +0100, Aurelien Degremont wrote:
> Eric Barton a écrit :
> > Sorry if these questions duplicates previous debate.
> > 
> > Have I understood correctly that the design allows individual objects
> > within a lustre file (i.e. stripes?) to be purged independently?
> > 
> > If so why is this needed?
> > 
> > I would have thought that when you purge a file, you need only record
> > the purged extent as an attribute of the whole lustre file and punch
> > its stripes to free the space.  Am I missing a use case?
> 
> Since the beginning CFS required this feature. It seems a lab ask for 
> it. I do not know who. Unfortunately we have no use case for what they 
> want to do with this.
> I'm wondering if their need could not be met with other features like 
> the internal Lustre migration...

That is my understanding also - I believe one of the Labs wanted this
(to be able to do HSM on a per-stripe basis instead of a per-file basis).

Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.