HPC Smackdown: What is the Best Clustered File System?

File systems, now there is a can a worms. Everyone has their favorite, yet no file system seems to do it all. There is also confusion about distributed file systems (like NFS) vs parallel file systems (like GPFS, Lustre, etc). And, what about the upcoming pNFS (parallel NFS) standard?

In case you need some background, check out our series on parallel file systems. (See part 1, part 2, part 3.)

So what is your opinion?