Does MPI-IO works with CephFS? Even omniscient Google is befuddled about this question. A quick Google search doesn’t turn up any positive results as of this writing.
Strictly speaking, NFS is a not a parallel file system, but rather a distributed file system. It is designed to let processes on multiple computers access a common set of files; it is not designed to give multiple processes efficient, concurrent access to the same file. Successfully performing MPI-IO on NFS-mounted file systems requires:
NFS is at version3;
Each NFS shared directory is mounted with the “no attribute caching” (NOACC) option enabled.
But still the performance will be poor!
CephFS is a traditional file system interface with POSIX semantics. And CephFS provides stronger consistency semantics than NFS. Is CephFS a true parallel file system?