Subject: RE: FW: I-D ACTION:draft-dusseault-dav-quota-01.txt

From: "Lisa Dusseault" <[email-masked]>
Date: Wed, 23 Oct 2002 09:48:15 -0700

The new draft of quota is out, but I never responded directly to these
comments (sorry).

> -----Original Message-----
> From: [email-masked]
> [mailto:[email-masked]] On Behalf Of Erik Seaberg
> Sent: Thursday, January 10, 2002 5:52 PM
> To: [email-masked]
> Cc: Lisa Dusseault
> Subject: Re: FW: I-D ACTION:draft-dusseault-dav-quota-01.txt
> 
> A client that wants to know how much storage is actually available in
> a collection has to PROPFIND each parent up to "/" looking for the
> minimum (quota-bytes - space-used-bytes) value.  That number should be
> a live property, since any server enforcing quotas must be able to
> produce it fairly efficiently.

That's true, but even knowing that the client can't necessary assure
their request will succeed.  I suspect that if the client just PROPFINDs
the current collection and subtracts space-used-bytes from quota-bytes,
the client will get an answer that works just as well 99% of the time.
If implementation experience suggests otherwise, I'd support this live
property as well.

> It's natural to want to handle this through quotactl(2) on Unix, but
> the draft says {DAV:}space-used-bytes "MUST include child collections
> and all resources inside those child collections" without regard for
> who created them.  Is the intent that all users MUST (or SHOULD) see
> identical {DAV:}quota-bytes and {DAV:}space-used-bytes values, or may
> an admin reveal quotas they've assigned to particular users?

It didn't say that it is without regard for who created them.  The
server is free to count any resource as 0 bytes against space-used for
all kinds of reasons (e.g. the resource is a binding).  The sentence was
intended to ensure that quota was understood to be recursive by clients
and servers.  Do you have better wording?

> Should a client be able to atomically reserve some of a collection's
> storage so expensive requests don't have to race with others to claim
> the last bytes?  It could be a header like
> 
> 	Expect: 100-continue, reserve; content-length="999999"
> 
> in a large PUT for example, or a live property on a collection
> allowing a reservation for several smaller resources or properties.
> 
In theory this would work already.  However I suspect servers
implementation of the Expect header is poor in reality.

Lisa

---

From: "Julian Reschke" <[email-masked]>
Date: Wed, 23 Oct 2002 20:35:18 +0200

> From: [email-masked]
> [mailto:[email-masked]]On Behalf Of Lisa Dusseault
> Sent: Wednesday, October 23, 2002 6:48 PM
> To: 'Erik Seaberg'; [email-masked]
> Cc: "Lisa Dusseault"@xythos.com
> Subject: RE: FW: I-D ACTION:draft-dusseault-dav-quota-01.txt
>
>
>

Actually, Erik also noted:

> On style, HTTP seems to use "octets" rather than "bytes" everywhere
> other than range requests.

I agree with him. Alternatively, one might also just use the term
"storage-units" -- that would give servers more freedom with little impact
to the clients.

[1] <http://lists.w3.org/Archives/Public/w3c-dist-auth/2002JanMar/0031.html>
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