We run a large Pressflow site with several webservers (load balanced with HAProxy). On every server the pressflow /files directory is shared via NFS3 to a master server. We see some limits in this NFS approach and would like to deploy a new, more performant and redundant system.
There are different choices like GlusterFS, MogileFS, NFS4, Lustre, ...
What do you use and how are your experiences so far with shared file systems?
Thanks for any best practice hints.