- From: Brian Korver <briank@xythos.com>
- Date: Thu, 11 Dec 2003 10:53:11 -0800
- To: Chris Sharp <csharp@apple.com>
- Cc: WebDAV <w3c-dist-auth@w3.org>
On Dec 11, 2003, at 10:30 AM, Chris Sharp wrote:
> Just getting around to understanding this thread. I totally agree, the
> quota-assigned-bytes seems unnecessary and confusing.
It does seem to be confusing to people. Do you have a proposal for an
alternative mechanism (or at least wording) that accomplishes
the same thing? Specifically, a mechanism set the quota (especially in
face of quota systems like the one you give in the example where
quota constraints are inherited from the parent)?
>
> On another note, I think there needs to be some clarification the way
> quota-available-bytes and quota-used-bytes work.
>
> Example:
>
> Initial State of Repository with a Quota management system:
>
>
> DAV:quota-available-bytes DAV:quota-used-bytes
> /A 95MB
> 5MG <--- used for somewhere for
> something
> /A/UploadDirectory 10MB
> 0
>
> A new 5MB resource is created at /A/UploadDirectory/new5MBFile:
>
> DAV:quota-available-bytes DAV:quota-used-bytes
> /A 90MB
> 10MB
> /A/UploadDirectory 5MB
> 5MB
>
> Pretty clear, however, if there is no quota differentiation on
> /A/UploadDirectory, the current draft of the RFC makes
> quota-used-bytes, which is really inherited from its parent,
> incongruent with quota-available-bytes on the same resource.
That's just one example of a quota system. As the draft points out:
Note that this is only one example quota system, and that other
quota systems are possible.
Do you think the text would benefit from having an example given using
a different quota system? I'm starting to think that would be a good
idea.
The draft does not mandate any particular quota system. IMHO it would
be a bad idea to do so.
> A diagram is in order:
>
> Initial State of Repository with a Quota management system:
> (quota system on /A only)
>
> DAV:quota-available-bytes DAV:quota-used-bytes
> /A 95MB
> 5MG
>
> A new 5MB resource is created at /A/UploadDirectory/new5MBFile:
>
> DAV:quota-available-bytes DAV:quota-used-bytes
> /A 90MB
> 10MB
> /A/UploadDirectory 90MB
> 5MB
>
> The sum of quota-available-bytes and quota-used-bytes is 95 on
> /A/UploadDirectory and not 100! Logically, if you get a request for
> quota-available-bytes on a resource /A/UploadDirectory and the quota
> is actually enforced on the parent, that you would essentially walk up
> the tree until you found an appropriate "mount point" based quota
> requirement. If this is true, the quota-used-bytes should do the same
> thing. Meaning, quota-used-bytes on /A/UploadDirectory would be the
> same as quota-used-bytes /A if /A/UploadDirectory did not contain a
> more specific quota rule.
>
> This is also an efficiency win for implementors. If an implementation
> has to support quota-used-bytes on an arbitrary URL, it is impractical
> to think that quota-used-bytes could be incrementally adjusted and
> would necessarily need to be calculated on-the-fly, which does not
> scale well for most implementations.
>
> How NFSv4 handles this situation?
>
>
> Also, under the "Notes" section, "What clients should expect" seems to
> have a sentence which is not grammatically correct.
> "This allows the space used by /~milele/public/ to be as
> large as the quota on /~milele/ allows (depending on the other
> contents of /~milele/) even if the quota on /~milele/ is changed."
>
> Regards,
>
> Chris.
> On Nov 14, 2003, at 2:27 AM, Stefan Eissing wrote:
>
-brian
briank@xythos.com
Received on Thursday, 11 December 2003 13:53:17 UTC