One thing I'm currently working on is a 2 node CentOS cluster using GFS as the shared file system, with the storage on a fibre attached HP MSA SAN. This is a proof of concept before investing in RHEL AS licences (which will be the better part of £2000). CentOS is free and is intended to clone RHEL as closly as possible, removing the Red Hat branding and of course professional support. The cluster suite and GFS are available in CentOS as they are both open source.
The hardware I am using is 2 HP DL580 G4 servers with 12GB of RAM, Qlogic HBA's, and an MSA1000 SAN. I'm using this guide on Red Hat's website and have been making my own notes along the way. I've got as far as installing cluster suite on one node but I'm unable to choose the grand unified lock manager as it doesn't appear as an option. I expect this may take a bit of reading to get working ... I'll post a mini howto here when I make some decent progress.
A while ago I undertook a similar exercise and had problems getting the HP ACU to see the SAN under Red Hat, I had to get HP involved as there were specific versions of the kernel and drivers required for it to work properly. I've noticed I have the same problem time time, but now I am on CentOS and it's the x64bit version, so it looks like I will have to experiment with driver versions and see what I can get to work without any support this time.
