With respect to metadata, the premise of PVFS^WOrangeFS is that providing full POSIX semantics (specifically locking?) makes the issues even worse, so it doesn'

With respect to metadata, the premise of PVFS^WOrangeFS is that providing full POSIX semantics (specifically locking?) makes the issues even worse, so it doesn't try, to decent effect. That may rule it out, for some applications like databases, though. Lustre has DNE for distributed metadata now. Presumably multi-tenancy would be important in this sort of application.