Re: NFS v4 client blocks when using UDP protocol

[Tom Haynes <tdh@excfb.com>]

On Tue, Mar 29, 2011 at 11:50:36AM -0400, peter.staubach@emc.com wrote:
> It does talk about NFS over UDP, interestingly, but the text on page 25, indicates that the transport of choice MUST be one of the IETF-approved congestion control transport protocols, of which, UDP is not one.
> 
> Perhaps some clean up of RFC3530bis and RFC5661 could include removal of the UDP mentions.

The text in 3530bis could be made to match that in 5661:

   It is permissible for a connectionless transport to be used under
   NFSv4.1; however, reliable and in-order delivery of data combined
   with congestion control by the connectionless transport is REQUIRED.
   As a consequence, UDP by itself MUST NOT be used as an NFSv4.1
   transport.  NFSv4.1 assumes that a client transport address and
   server transport address used to send data over a transport together
   constitute a connection, even if the underlying transport eschews the
   concept of a connection.

But as we can see 5661 is very strong.

> 
> 		ps
> 
> 
> -----Original Message-----
> From: linux-nfs-owner@vger.kernel.org [mailto:linux-nfs-owner@vger.kernel.org] On Behalf Of Menyhart Zoltan
> Sent: Tuesday, March 29, 2011 11:26 AM
> To: Chuck Lever
> Cc: linux-nfs@vger.kernel.org
> Subject: Re: NFS v4 client blocks when using UDP protocol
> 
> Chuck Lever wrote:
> > Zoltan-
> >
> > As far as I know, NFSv4 is not supported on UDP transports.
> >Some of it may work, but no warrantee, either expressed or implied, is given.  :-)
> 
> Do you mean the Linux implementation?
> Because the RFC 3530 speaks about how to do NFS v4 over UDP and UDP6.
> 
> Thank you,
> 
> Zoltan
> 
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-- 
Tom Haynes
ex-cfb