[Lustre-discuss] Setting up quotas after the fact

[Sebastien Piechurski]

Gregory,

Lustre does not (yet) store file sizes on the MDT (there is a project called SOM for Size On MDT, which is currently suspended I think). Instead, when a file size is requested, each OST holding objects for this file are queried for these objects size, which are then summed up.

So, the quotacheck actually hits the OSTs. 

> -----Original Message-----
> From: lustre-discuss-bounces at lists.lustre.org 
> [mailto:lustre-discuss-bounces at lists.lustre.org] On Behalf Of 
> Gregory Matthews
> Sent: vendredi 11 mars 2011 17:52
> To: lustre-discuss at lists.lustre.org
> Subject: Re: [Lustre-discuss] Setting up quotas after the fact
> 
> That sounds to me like it is only hitting the MDT and not the OSTs. 
> which would mean if you have a lustre system that has been 
> upgraded from 
> an older version, most of the file sizes reported on the MDT will be 
> zero and this must affect the validity of the quotacheck...
> 
> GREG
> 
> Johann Lombardi wrote:
> > That's very good news. Thanks for the feedback Sébastien.
> > 
> > Johann
> > 
> > On Fri, Mar 11, 2011 at 06:29:11AM -0600, Sebastien 
> Piechurski wrote:
> >> Just to confirm what Johann said, I ran 2 weeks ago a complete
> >> quotacheck on a 600TB filesystem with ~50 millions inodes in
> >> approximately 5 minutes too. The filesystem is distributed 
> across 28 OSS
> >> (168 OSTs of 3.6TB each).
> >> So you should be able to run your quotacheck quite quickly.
> > 
> 
> 
> -- 
> Greg Matthews            01235 778658
> Senior Computer Systems Administrator
> Diamond Light Source, Oxfordshire, UK
> 
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