I have similar problems but they are related to obtaining user login 
info over the network and not NFS.

Are you using ldap or NIS for user authorization/authentication ?
Do you use nscd (name switch caching daemon) on the clients ?


Jan Schulze wrote:
> Hi all,
> 
> I recently upgraded a number of NFS clients from SL 4.2 to SL 5.1. The
> NFS server is still running SL 4.2. Clients are acting very slow, e.g.
> 
> - after SSH authentication, it takes about 5 sec. for the console prompt
>  to appear
> - every 'ls' is slow
> - compiling stuff is terribly slow
> 
> It seems to have something to do with NFS - I'm having some NFS-mounted
> directories in my $PATH (TC shell). When I throw them out, everything is
> working as expected (e.g. compiling gcc was ~9 times faster). Please
> note, that the same $PATH does not noticeably slow things down on the
> old 4.2 systems.
> 
> I did comparisons compiling gcc on the old and new systems while running
> tcpdump. I found, that the new systems performed a lot more NFS lookups
> (by factor ~4). Everything else seemed normal.
> 
> File transfer to the NFS server is OK, no speed problems here. Tcpdump,
> however shows a lot of lines like this one, when copying files:
>   18:19:56.571906 IP bsnode02.0 > morphin.nfs: 1448 null
> 
> Load on the NFS server is much higher than before. I'm a little bit at a
> loss - how could I debug these issues further?
> 
> 
> Regards,
> Jan


-- 
Chris Hunter
Systems Programmer, Astronomy Yale University