Re: [nfsv4] [FedFS] Multiple FSL resolution

[James Lentini <[e-mail]>]

On Wed, 9 Dec 2009, [e-mail] wrote:

> 
> Either an easily answered question or a possible topic for discussion in
> tomorrow’s FedFS call.
> 

We can certainly discuss this during today's meeting. I will place it 
on the agenda.

> 
> The requirements spec
> (http://www.ietf.org/id/draft-ietf-nfsv4-federated-fs-reqts-06.txt) talks
> about associating multiple FSL's with an FSN where the file sets referred to
> by the FSL's are replicas of one another.  Maintenance of the replicas is
> outside the scope of FedFS.   
> 
>  
> 
> When a client traverses a junction that refers to an FSN which has multiple
> FSL's associated with it the file server queries the relevant NSDB for the
> FSLs associated with the FSN (section 3.2, step 4).    But only one of the
> potentially multiple FSLs is returned to the client in the form of a
> protocol specific referral (section 3.2, step 5).     

This text is only an example. If client access protocol supports 
multiple referral targets, the fileserver may return more than one. In 
fact, NFSv4's fs_locations and NFSv4.1's fs_locations_info allow for 
multiple targets.

> How does the server decide which of multiple FSLs to return to a 
> client?

The process the server uses is implementation specific. The server 
might return all the FSLs or have some algorithm for picking a subset 
of the FSLs.