Hello, I'm new to this forum and fairly new to Linux.
I have recently upgraded to Mandriva 2007 Spring (the One version)
on both of my computers from Mandriva 2005. I want to be able to
share files between the two computers since one of them has a much
larger hard disk. I chose NFS to do this because I read that it is
simple to install and uses very little overhead.

I've followed the various how-to's and tutorials on setting up
NFSv4. My /etc/fstab on both pc's looks like this:

/dev/hda1 / ext3 defaults 1 1
/dev/hda6 /home ext3 defaults 1 2
none /proc proc defaults 0 0
/dev/hda5 swap swap defaults 0 0
rpc_pipefs /var/lib/nfs/rpc_pipefs rpc_pipefs defaults 0 0
nfsd /proc/fs/nfsd nfsd defaults 0 0

my /etc/exports looks like this:

# /etc/exports: the access control list for filesystems which may be exported
# to NFS clients. See exports(5).
/home/USR/shared IP#(rw,subtree_check)

on pc2 and this:

# /etc/exports: the access control list for filesystems which may be exported
# to NFS clients. See exports(5).
/home/USR/shared IP#(rw,subtree_check)

on pc1

hosts.deny for both:

portmap:ALL
lockd:ALL
mountd:ALL
rquotad:ALL
statd:ALL

hosts.allow for both:

#
portmap: IP#,IP#
lockd: IP#,IP#
rquotad: IP#,IP#
mountd: IP#,IP#
statd: IP#,IP#

the ps aux command tells me that portmap, lockd, rquotad, mountd,
statd, nfsd, and ps idmapd are all running.

So everything is set up as the tutorials say they should be.
When I attempt to mount the shared stuff on either pc, though,
I get the following error message:

#mount -t nfs4 IP#:/ /mnt
mount: IP#:/: can't read superblock

What am I doing wrong? How do I fix this? Any help would be appreciated. Thanks.

try,

mount -t nfs4 192.168.1.100:/home/USR/shared /mnt

You are trying to mount the root directory, but you only exported /home/USR/shared.
So you would have to mount
(or export '/' if that is what you want to do)

I suppose the symmetric setup on both machines means that you really want both machines to act as nfs server for each other?

I thank you both for your prompt replies but I'm afraid that
didn't work. I get the same error message. Could it be that
my kernel is not configured for nsf4? It's the default kernel
that ships with M'2007 Spring-One. Could it be that the USR
is the same on both machines?

The setup is symetrical because, yes, I would like both machines
to act as servers. Would this cause problems? Is there something that I forgot to install? I've been trying to get this
to work for the better part of a week and thought it was going to
be a simple setup when I started. Jokes on me I guess.

A little further testing revealed the following:

# mount -a
mount: rpc_pipefs already mounted or /var/lib/nfs/rpc_pipefs busy
mount: according to mtab, sunrpc is already mounted on /var/lib/nfs/rpc_pipefs

adding the following line to /etc/fstab:
IP#:/home/USR/shared /mnt/nfs nfs4 soft 0 0
resulted in:
mount: IP#:/home/USR/share2: can't read superblock

changing that same line to:
IP#:/home/USR/shared /mnt/nfs nfs soft,nfsvers=2 0 0
resulted in
mount: failed to probe ports on NFS server IP#
after about 10 minutes.

changed line to:
IP#:/home/USR/shared /mnt/nfs nfs soft,nfsvers=4 0 0
resulted in:
'vers=4' is not supported. Use '-t nfs4' instead.

changed line to:
IP#:/home/USR/shared /mnt/nfs nfs4 soft 0 0
resulted in:
a return with no message. Success?? I was unable to find
anything in /mnt/nfs. Also, the mount command didn't list any
new mounts (not that I know if it should or not).

attempting mount -a again, with the same fstab entry resulted
in the "can't read superblock" error, again.

I'll try more later.