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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
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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?
- NFS V4 Working Group of the IETF
- NFS V4.1 Specification (NFS V4 Status Page)
- NFS Version 4 Minor Version 1
- pNFS Problem Statement
Garth Gibson (Panasas), Peter Corbett (Netapp), Internet-draft, July 2004,
- Linux pNFS Kernel Development (CITI)
- Connectathon.org – Interoperability Testing Forum
- Open Source NFS V4 Reference Implementation (CITI)
- pNFS OpenSolaris Project
- Linux Journal: Parallel NFS (pNFS) Bridges to a Mature Standard
- Petascale Data Storage Institute
- Scale your file system with Parallel NFS,
IBM | November 11, 2008
- Entersprise Storage Forum: "NFS Enters a Parallel Universe",
August 7, 2008
- ACM Queue: Standardizing Storage Clusters,
vol. 5, no. 6 - September / October 2007
- StorageMojo: pNFS technical intro ,
October 15, 2007
- eWeek: HPC's New Storage Rock Star,
July 3, 2007
- Data Mobility Group: Parallel NFS: Finally, NFS Optimized for Clusters, May 30, 2007
- ZDNet: Warp speed file serving with pNFS, May 23, 2007
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