The other useful inputs were
1) Some of the cheaper PC ethernet cards have trouble handling large packet sizes used by
NFS.
2) Some info from Adrian Cockcroft's SE toolkit (all values pertain to client rpc
nfsstat -c )
If ( (0.05 * calls ) <= timeout ) && badxid == 0,
Packets are not making it to or from the NFS server. Fix network hardware or
reduce the NFS packet size.
(the above condition was true for me with version 3 nfs ).
Thanks
Basavaraj