[Beowulf] how large of an installation have people used NFS with? would 300 mounts kill performance?

[Rahul Nabar]

Our new cluster aims to have around 300 compute nodes. I was wondering
what is the largest setup people have tested NFS with? Any tips or
comments? There seems no way for me to say if it will scale well or
not.

I have been warned of performance hits but how bad will they be?
Infiniband is touted as a solution but the economics don't work out.
My question is this:

Assume each of my compute nodes have gigabit ethernet AND I specify
the switch such that it can handle full line capacity on all ports.
Will there still be performance hits as I start adding compute nodes?
Why? Or is it unrealistic to configure a switching setup with full
line capacities on 300 ports?

If not NFS then Lustre etc options do exist. But the more I read about
those the more I am convinced that those open another big can of
worms. Besides, if NFS would work I do not want to switch.

-- 
Rahul