I have 16 nodes gfs cluster for it built on GFS but afaik GFS is
stable and usable only for red hat (for other distros there's openGFS
which is imho different ) . Setting it up took me 2 days on Quality
Assurance and one day on production . There's a very robust way of
managing the cluster and whole software is very very nice ;) One thing
that's rather expensive is fiberchannel SAN that is important when
using GFS .. i found no other way to set it up that with EVA (or other
SAN with FC) with one exported logical volume for 16 machines
connected to it with brocade Fiber Channel switch ... but
effectiveness of such thing is very big ;)