Re: FreeBSD, Linux and NFS

[Clifton Royston <cliftonr@lava.net>]

On Wed, Jan 26, 2000 at 12:39:48AM +0100, Thomas Keusch wrote:
> Ok, so if I get things right, which I think (hopefully) I do, this means
> that Linux mounts NFS filesystems via TCP/IP, the FreeBSD server forces
> NFS v2 via the "-2" switch given to mountd and the 4 nfsd only serve
> stuff via TCP/IP ("-t" argument).
> 
> But, stressing my home LAN a little bit the last few days, it happened
> to me three times already that the server simply stops serving the fs
> (or NFS in general, I didn't check before restarting stuff :-( ),
> while it stays perfectly functional in all other ways I can think of.

I don't remember the exact circumstances, but I believe one of the
standard problems with running many implementations of NFS over TCP is
that if the TCP session "breaks down", in most implementations the NFS
client will never open a new TCP connection; i.e. it relies on TCP/IP
being not just more reliable, but infinitely reliable, which it just
isn't.

...
> *Finally* :-)
> ... finally this is the error message I get on the Linux box syslog:
> 
> dante kernel: nfs: server darkstar not responding, still trying
> 
> Any ideas on that one?

It could be what I'd described above.

 
> Is my assumption, that _only_ NFS v2 via TCP/IP, *NOT* UDP, will work
> between FreeBSD and Linux, correct? At all? If it ever was?
> (I just seem to have remembered this sort of stuff popping up on the
> lists and v2/tcp NFS being the solution)
> 
> So, is there some help for me?

If you want to verify it, use netstat and lsof on both boxes to look
for the NFS/TCP connection when this problem exists, and see if it
still exists on both sides.  If either side has lost the TCP
connection, that's probably it there.

I would recommend trying to switch it to UDP and see if that helps. 
  -- Clifton

-- 
 Clifton Royston  --  LavaNet Systems Architect --  cliftonr@lava.net
        "An absolute monarch would be absolutely wise and good.  
           But no man is strong enough to have no interest.  
             Therefore the best king would be Pure Chance.  
              It is Pure Chance that rules the Universe; 
          therefore, and only therefore, life is good." - AC