Re: [nfsv4] Last call for NSDB Protocol for Federated Filesystems (Oct 4 - Oct 22nd)

[Nicolas Williams <[e-mail]>]

On Wed, Nov 03, 2010 at 04:19:16PM -0600, Robert Thurlow wrote:
> James Lentini wrote:
> >In the process of reviewing the revised text, Chuck, my
> >co-authors, and I have have been considering the utility of
> >including this annotation mechanism. Before LDAP was chosen for
> >the NSDB protocol, this attribute was created to allow private
> >schema extensions. Given our use of LDAP, this attribute may be
> >obsolete.
> >[...]
> >Are there objections to removing the fedfsAnnotation attribute
> >from the schema and recommending that schema extensions be handled
> >as described above?
> 
> I wish to create a management application which uses the
> annotations fields as described in the current NSDB schema,
> and I think the use case really requires the current form
> of the specification, and not schema extensions.
> 
> The interesting-to-me use case is a kind of a back pointer -

I think we should pre-define an attribute for back pointers, as that
seems valuable even though it's unreliable.

I think a free-form text annotation for sysadmins to make notes is also
a good idea.

I don't think a free-for-all attribute/value namespace is a good idea,
as then each vendor will add random things that will then create interop
problems (because of collisions, because others will feel pressured to
implement the same attributes with undocumented/obscure/unstable
semantics, ...).  OTOH, a FedFS-specific attribute/value namespace
subject to IANA registration would be fine, and even desirable for the
reasons that you state.

> [...]
> The unreliability is why this is not something I have tried
> to make a core part of the NSDB protocol.

Just because it's unreliable doesn't mean it's a bad idea to have it in
the core spec.  Hints can be useful even if they're wrong some of the
time.

> If I need to do this with LDAP schema extensions, someone
> must go through the non-standard LDAP management interface
> to get these bits added to the schema before I do my first
> bit of work in my management application.  [...]

Right, so let's get this attribute in _now_, while it's still early
enough :)

Nico
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