Thanks to those who replied, in particular <sysadmin_at_astro.su.se>, who helped me
understand all this. The problem seems to lie in the interpretation of the
exports file on Linux. Because we export to al lot of machines we use netgroups
to do the exports. On most Unix systems you just give the netgroup name in
place of a host name. E.g. on our Alphas we would have
/home/staff -access=cee.net
But on Linux systems you have put put an _at_ sign in front of a netgroup name
/home/staff _at_cee.net(rw,insecure)
It then seems that when you access an NFS server using the
/net/machine/filesystem syntax, the first thing the client does is ask the
server for its exports file. It then actually mounts all the filesystems that
are exported to it, rather than just the one you ask for. What is happening is
that the Tru64 systems look at the exports file that comes back, doesn't
understand the _at_netgroup syntax and therefore just bombs out without trying to
mount any filesystem. If instead the Linux server had just a line saying
/home/staff odin(rw,insecure)
then the Tru64 machine can mount that with no problems. And because it reads
all of /etc/exports then if even one line has an _at_ sign in it, nothing is
mounted.
There appears to be some discrepancy between the RFCs describing NFSv2 and
NFSv3 on how the client should interpret the exports file, so maybe the problem
would go away if we ran NFSv3 on our Linux server, but as that gives us other
problems we have to stick with v2 in the meantime.
On Fri, Feb 02, 2001 at 02:28:06PM +0000, Hugh M. Conner wrote:
> We have a wide range of systems in our dept. and share filesystems among them
> all. We are experiencing some problems with NFS mounting under certain
> circumstances. In particular where we have a Linux NFS server and try to access
> it from a Tru64 machine via the automounter. (We are running quite an old
> release by the way - 4.0B). Manual mounting works fine
>
> odin# mount amaterasu:/home/staff /mnt
> ^^^^ ^^^^^^^^^
> Tru 64 machine Linux machine
>
> Also mounting via the autmounter works in certain areas
>
> odin# cd /u1/staff/fred
>
> Here there is a YP map auto.u1_staff where "fred" is mapped to
> amaterasu:/home/staff/fred
>
> However the one that fails is
>
> odin# cd /net/amaterasu/home/staff
> ksh: /net/amaterasu/home/staff: not found
>
> where the automounter uses the hosts NIS map. We can use this to access other
> types of NFS servers ok, eg. /net/osiris/home/pg works where osiris is another
> Alpha.
>
> We have found other versions of Unix with the same problem - e.g. SunOs 4 and
> Ultrix (yes we still have some of these). On the other hand HP, SGI and SunOs 5
> machines work fine with Linux. Has anyone else come across this and knows what
> is causing the problem.
--
Hugh M. Conner
Computing & Electrical Eng.
Heriot-Watt University
hmc_at_cee.hw.ac.uk
"Life is a lemon, and I want my money back"
Received on Mon Feb 05 2001 - 15:56:27 NZDT