Is doing mount -u -o udp useful for you on an NFS mount?

[Rick Macklem]

Jeremy Chadwick wrote:
> On Wed, Jan 25, 2012 at 11:01:41PM -0500, Rick Macklem wrote:
> > Using a "mount -u" to change from TCP to UDP for an
> > NFS mount is somewhat broken for both NFS clients.
> > To make it work correctly is not trivial.
> >
> > As such, I'd like to find out if anyone needs this
> > capability? (Note, I am not talking about UDP mounts
> > in general, just the case of switching a TCP mount to
> > a UDP mount without doing an unmount/mount.)
> 
> I've never seen any SAN admin do this, even on our production server
> at
> work (Solaris with a NetApp SAN). When it comes to NFS, the moral of
> the story is always "reboot the machine" (which is good anyway, make
> sure everything comes up on boot, else months from now you'll find out
> the hard way).
> 
> However, to squelch people from doing it, could mount_nfs(8) actually
> be
> modified to spit out a nastygram when someone attempts to do this, so
> at
> least the admin would know that such isn't supported due to the
> extreme
> complexities involved?
> 
I've just committed a patch that sends a log warning message when
someone does this.

Thanks for the suggestion, rick