[Linux-cluster] NFS/GFS performance tuning

[David Merhar]

We have the cluster running without problem (RHEL5.3, gfs2).   The  
improvements over the last 6 months are noticeable, and appreciated.

The problem:
Local file access (cluster member) is 160/135 r/w.
rsh access across the network is 130/115.
nfs access across the network is 45/27.

Our test is
dd if=/dev/zero  of=/nfs/mount/test_file bs=1M count=10000
The remote system is also 5.3.

We've tinkered with a whole lot of settings in nfs server/client, gfs2  
mount and tune parameters, and the network itself.  We've also played  
with dd flags. Yet we can't cross the 27 Mb/s write threshold.  (But  
we're willing to try again.)

Any advice?

djm