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pNFS.com is a resource for information regarding Parallel NFS and its standardization as a revision to NFS v4 through the IETF. In December, 2008, the IESG approved the internet drafts as Proposed Standards.
IESG promotes Internet Drafts to Proposed Standard status
The Internet Drafts describing the pNFS standards have reached an important milestone: promotion from an Internet Draft to a Proposed Standard. The documents are now in the hands of the RFC editors, and we expect official RFC numbers to be issued in 2009. The NFS4.1 standard document is large because it includes a complete description of all of NFSv4 as well as the new 4.1 features. There are two companion documents that describe the object layout and block layout for pNFS storage.

  • nfsv4-minorversion1 This Internet-Draft describes NFS version 4 minor version one, including features retained from the base protocol and protocol extensions made subsequently. Major extensions introduced in NFS version 4 minor version one include: Sessions, Directory Delegations, and parallel NFS (pNFS).
  • nfsv4-pnfs-obj This document provides a specification of the object-based layout type definition to be used with the NFSv4.1 protocol. As such, this is a companion specification to NFS version 4 Minor Version 1.
  • nfsv4-pnfs-block This document provides a specification of a block based layout type definition to be used with the NFSv4.1 protocol. As such, this is a companion specification to NFS version 4 Minor Version 1

Vendors line up behind pNFS at SC08
The pNFS BOF at SuperComputing08 had represtatives from EMC, IBM, LSI, NetApp, Panasas, and SUN. Also attending were the Linux NFS maintainers and others active in the pNFS development community. The slides from the presentations describe the plans these vendors have for pNFS support. The slides include status from different vendors, as well as some performance reports on the impact of parallel I/O on application speedup.

What is pNFS?
Parallel NFS (pNFS) is a part of the NFS v4.1 standard that allows clients to access storage devices directly and in parallel. The pNFS architecture eliminates the scalability and performance issues associated with NFS servers in deployment today. This is achieved by the separation of data and metadata, and moving the metadata server out of the data path as shown in the diagram below.

Note that pNFS supports the use of 3 storage protocols in the data path: blocks, objects and files.

Why is it important?
pNFS is important because it brings together the benefits of parallel I/O with the benefits of the ubiquitous standard for network file systems (NFS). This will allow users to experience increased performance and scalability in their storage infrastructure with the added assurance that their investment is safe and their ability to choose best-of-breed solutions remains intact.

    Benefits of Parallel I/O
  • Delivers Very High Application Performance
  • Allows for Massive Scalability without diminished performance

    Benefits of NFS (or most any standard)
  • Ensures Interoperability among vendor solutions
  • Allows Choice of best-of-breed products
  • Eliminates Risks of deploying proprietary technology
Download Source Code for pNFS
If you want to get a head start with pNFS you can download the latest development source code for the pnfs-enabled Linux kernel from linux-nfs.org (provided under the GNU General Public License, Version 2) and the OpenSolaris code from opensolaris.org (under the OpenSolaris Binary License)

The Linux kernel supports various layout drivers for files, objects, and blocks, as well as experimental back-end file systems, such as spnfs and pnfs support for the GFS2 clustered file-system.

Other back-ends are available from several vendors, including EMC (HighRoad), IBM (GPFS2), and Panasas (ActivStor).

If you have questions regarding the source code provided here please contact us at pnfs-info@panasas.com.

Panasas source code is contributed to the open source community by Panasas with the express intention of furthering the rapid adoption of pNFS.
Where can I find more information?
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