[Lustre-discuss] NFS Export Issues

[Bernd Schubert]

On Tuesday, July 20, 2010, William Olson wrote:
> > As far as i remember we had to explicitly align the "mounting" user uids
> > and gids. So the mounting uid:gid must be known (/etc/passwd and groups 
> > i think) on the mds and allowed to mount stuff.
> > 
> > Could it be a "root squash" problem by accident ?
> 
> I've tried it explicitly with the no_root_squash option and it still
> behaves the same way..
> What I find really frustrating is that if I unmount lustre, I can mount
> the same nfs export, no problems.  As soon as lustre is mounted to that
> directory I can no longer mount that nfs export.
> I don't understand where it's failing..
> 
> Thanks for all your help so far, any more ideas?

Have you tried to add "fsid=xxx" to your exports line? I think with recently 
Lustre versions (I don't remember the implementation details) it should not be 
required any more and so it should not with recent nfs-utils and until-linux 
(the filesystem uuid is automatically used with those, instead of device 
major/minor as fsid), but maybe both type of workarounds conflict on your 
system?

You also might consider to simply use unfs3, although performance will be 
limited to about 120MB/s, as unfs3 is only single threaded. It also does not 
support NFS locks.

If it still does not work out, you should enabled lustre debugging, nfs 
debugging and you probably should use wireshark to see what it going on.


Hope it helps,
Bernd

-- 
Bernd Schubert
DataDirect Networks