[AFS3-std] Re: [OpenAFS-devel] Re: Hackathon Summary

[Christof Hanke]

Am Freitag, 9. Oktober 2009 19:22:46 schrieb Andrew Deason:
> On Fri, 9 Oct 2009 15:12:14 +0100
>
> Simon Wilkinson <sxw@inf.ed.ac.uk> wrote:
> > Generic Quotas
> > --------------
> >
> > Christof had raised the issue of providing a more generic quota
> > mechanism, which allows more flexible definitions of what quota might
> > be (rxosd would like to be able to apply a separate quota to files
> > under a certain size, for example)
> >
> > We discussed implementing this as a set of tag value pairs, with each
> > pair having a globally defined meaning. Individual tags need not be
> > implemented on every fileserver - there should be an RPC by which
> > clients can determine which tags a fileserver supports. We want to
> > implement this by revising existing RPCs which take quota values, and
> > use it to replace the quota values that those RPCs already contain.
> >
> > Christof will write a document describing this, but we won't block
> > the RPC refresh on it
>
> Upon reading this, I thought, why should we limit this to quotas? Should
> we have a more generic extensible volume metadata RPC that can be used
> for any volume-related purpose? I would imagine an xattr-like
> functionality at the volume level could be potentially useful for
> numerous things.

It was not meant for quotas only, but also for usage.
We agreed just to change the volintInfo-structure for that.

Thus, basically the tags to be used which are obvious for me now are :
* block-usage 
* block-quota
* file-usage
* file-quota

which can be all of the same type (afs_uint64).

Something more generic would mean to support more data-types than afs_uint64, 
which could be done using the techniques for dumping the volume, but I'm not 
sure if we should do all that in one step.