Ok, so NFS has never really been my cup of tea. Complicated and the problem with the root user and locking and what not have always made me get all itchy when thinking about or using NFS.
Enter pNFS, the NFS 4.1 invention that truly suddenly makes the NFS technology so much interesting for high performance solutions. I also thinkÂ it is a bit unknown so I thought I’d help to share the knowledge about this to you my dear readers. The p in pNFS stands for parallel. The whole idea is that the single NFS server just provides meta data back to the client, with enough information to allow the client to read the actual payload data directly from the storage server(s), that then supposedly are different ones than the main meta data server
(picture from www.nexenta.org)
As you can see on this fancy picture, it allows each client to speak directly to the storage device to get or send the data. This allows them to avoid using a single bottleneck NFS server.
NFS 4.1 and pNFS are IETF standards, RFC5661 to RFC5664. The first one being 616 pages long and one of the largest RFCs I’m aware of.