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RE: I-D ACTION:draft-ietf-webdav-quota-01.txt

From: Julian Reschke <julian.reschke@gmx.de>
Date: Thu, 27 Mar 2003 20:49:22 +0100
To: "WebDAV" <w3c-dist-auth@w3.org>
Message-ID: <JIEGINCHMLABHJBIGKBCOEDHGOAA.julian.reschke@gmx.de>

> From: w3c-dist-auth-request@w3.org
> [mailto:w3c-dist-auth-request@w3.org]On Behalf Of Brian Korver
> Sent: Thursday, March 27, 2003 1:05 AM
> To: Julian Reschke
> Cc: WebDAV
> Subject: Re: I-D ACTION:draft-ietf-webdav-quota-01.txt
>
>
>
> On Tuesday, March 25, 2003, at 01:00  PM, Julian Reschke wrote:
> >
> > The reason I raised this is because I feel that a "disk full" indeed
> > is an
> > error condition on the server (thus 5xx), but a failed request due to
> > exceeded quota limits happens *on purpose* -- the server theoretically
> > *could* perform the request, but it doesn't want to.
> >
> > But as Geoff already stated, this is really not an important issue --
> > even
> > more so if we have well-defined condition names that we can send in
> > error
> > response bodies.
> >
> > I'd prefer to focus the discussion on the other issues I mentioned
> > (such as
> > what is the quota model the spec describes, and do we really need to
> > describe a specific model at all; or: are physical disk limits a
> > special
> > case of quotas? -- RFC3010 distinguishes both).
> >
> > Julian
>
> Julian,
>
> I was thinking that physical disk limits are just another class of
"quotas".
> That probably isn't clear enough from the spec, and should probably be
> stated.

Yes and no. It depends on who is asking. Note that RFC3010 (which I think we
all like :-) distinguishes between both.

Earlier today, Stefan E. showed that lumping disk limits and quota into the
same property can lead to very surprising effects. Do we really want that?

> The alternative is to report two numbers, quota-limit and something like
> "space-limit", but I think we basically agreed that reporting back one
number
> would be better than multiple numbers (given that the server should know
> which of the numbers is the "best" one to represent the space  constraints
> on that server).

The issue here is that disk limits *behave* differently than quotas. For
instance, a "quota error" usually can be resolved by the user, by deleting
some of his own files, while a "disk full" condition may possibly not (other
user may take up the disk space, so there's no way for the affected user to
recover/continue). Also, recovery from both conditions may be different --
the person you need to contact to get a higher quota might be somebody else
than the person that's able to free up physical disk space (or add new
disks).

Here's another proposal how we *could* inherit RFC3010 properties without
much effort in WebDAV -- just use their welldefined names from RFC3010, and
put them into the IETF namespace reserved for individual RFCs, for instance:

<D:prop xmlns:D="DAV:" xmlns:NFS="urn:ietf:rfc:3010">
  <NFS:space_freel>12345678</NFS:space_free>
  <NFS:space_total>1234567890</NFS:space_total>
  <NFS:quota_used>123456</NFS:quota_used>
  <NFS:quota_avail_hard>1234567</NFS:quota_avail_hard>
</D:prop>

(we'd just have to state how RFC3010 terminology maps to WebDAV resources)

Julian

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Received on Thursday, 27 March 2003 14:49:31 GMT

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