[OpenAFS] AFSDB vs SRV records??

Jeffrey Hutzelman jhutz@cmu.edu
Thu, 19 May 2005 17:35:40 -0400

On Thursday, May 19, 2005 08:39:18 AM +0100 Chris Crowther 
<chris@jm-crowther.co.uk> wrote:

> Derrick J Brashear wrote:
>> AFSDB records, yes. SRV records, no idea.
> 	AFSDB is rather simple.  It's just "AFSDB <type> <host>." where type is
> either 1 or 2 (normally 1 I think - 2 is something to do with DCE).
> 	I've not seen a specification for SRV entries for AFS.  If it did exist
> it, I suspect it'd be something like "_afs._udp IN SRV <priority>
> <weight> 7003 <host>.", assuming of course you want to locate the vldb;
> but given it's not defined anywhere, that I've seen, it's probable we're
> just waiting for someone to create an offical definition and use it.

There is no specification for SRV records for AFS, and it seems unlikely 
that there will be anytime in the near future.  The existing AFSDB RRtype 
does what we need, is well-support by both nameservers and AFS 
implementations, and is widely-deployed.

Specifying the use of SRV records would be complex (what service name do 
you use?  hint: it's not 'afs'), would likely lead to confusion (do I need 
to publish AFSDB, SRV, or both?), and would be fairly complex to implement 
correctly (current cache managers do not implement anything resembling 
weighting, and have only a primitive priority mechanism).  The use of SRV 
records for AFS without a specification it would be even worse -- the SRV 
rrtype specification specifically warns against using SRV records for 
services for which its use is not defined (I believe it says MUST NOT).

-- Jeffrey T. Hutzelman (N3NHS) <jhutz+@cmu.edu>
   Sr. Research Systems Programmer
   School of Computer Science - Research Computing Facility
   Carnegie Mellon University - Pittsburgh, PA