high availability

Hey guys, anyone ever applied the Linux Virtual Server (or any other similar) architecture on webservers running php applications? the Linux Virtual Server homepage, if anyone is interested, is http://www.LinuxVirtualServer.org I was wishing to implement something like that, but I'm not quite sure how can php fit there, the basic idea of this architecture is to have a load balancer box which handles connections (http/https in my case) from clients and passes them on the the real servers. Those real servers can share a distributed fault-tolerance filesystem like CODA. That way I can have a single copy of the php scripts that will be used by all servers, now, I'm wondering about the following issues: - Does php works fine over a CODA filesystem ? - will it be enough to just set the session.save_path on all servers to be stored at my CODA filesystem so all webservers can share sessions information or should I write a session class/function to store that info on a shared SQL backend instead? - what database do you think it will fit into this architecture? (something with mature load-balancing, high-availability features) - do you know any better alternatives to this architecture? Any suggestions are very very welcome :)) Regards, Alex Verstraeten Buenos Aires, Argentina.