"However, one domain not traditionally well served by
NFS is high-performance computing (HPC), where data files are very
large, sometimes huge, and the number of NFS clients can reach into
the thousands. (Think of a compute cluster or grid composed of
thousands of commodity computing nodes.) Here, NFS is a liability,
because the limits of the NFS server—be it bandwidth, storage
capacity, or processor speed—throttle the overall performance
of the computation. NFS is a bottleneck.
"Or, at least it was.
"The next revision of NFS, version 4.1, includes an extension
called Parallel NFS (pNFS) that combines the advantages of stock
NFS with the massive transfer rates proffered by parallelized input
and output (I/O). Using pNFS, file systems are shared from server
to clients as before, but data does not pass through the NFS
server. Instead, client systems and the data storage system connect
directly, providing numerous parallelized, high-speed data paths
for massive data transfers. After a bit of initialization and
handshaking, the pNFS server is left "out of the loop," and it no
longer hinders transfer rates."