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

Jeremy Chadwick freebsd at jdc.parodius.com
Thu Jan 26 08:22:09 UTC 2012


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?

-- 
| Jeremy Chadwick                                 jdc at parodius.com |
| Parodius Networking                     http://www.parodius.com/ |
| UNIX Systems Administrator                 Mountain View, CA, US |
| Making life hard for others since 1977.             PGP 4BD6C0CB |



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