Best cluster OS

[Nick I]

Hi,
At www.clusterbuilder.org/FAQ <http://www.clusterbuilder.org/FAQ> there is a
question about what OS and cluster management software are the best for a
cluster system. Does anyone have any advice on FreeBSD as a cluster OS?

Here is the question:

"I'm bulding a project for a cluster that consists on 64 machines running
each 2x Dual Core AMD Opteron with 2GB of memory per core (8GB per machine).
We already have everything else accounted for except for the software. We
have serious doubts on what would be best for the OS and the cluster
management software. The OS has to be open source. Please give me some
advice on what you think you be the best performance solution for it. It
doesn''t matter if it's not free. "

Also, if anyone has any advice on cluster management software, please send
it. I am trying to build a knowldgebase of different opinions on software.

Thanks,
Nick