The Oracle Cluster File System could already be a nice alternative to GFS and Coda - at least if this really happens:
The Linux developer responsible for the Linux Kernel 2.6, Andrew Morton, wants to include the Oracle Cluster File System version 2 in the official Linux Kernel as soon as possible. Linux 2.6.14 could already contain OCFS 2 and would then be the first cluster component in the official Linux Kernel.
The previous cluster file systems suffer from the lack of integration - most of the time you can't use them in every kernel version. What is interesting to me is how independent the nodes really are and whether there is also a single point of failure in the Oracle Cluster File System, as there is e.g. the Locking daemon in OpenGFS. So far, we have not been very successful in evaluating cluster file systems in the company, actually they were all somehow stupid ...