Parallel NFS (pNFS) Block/Volume Layout
RFC 5663

Internet Engineering Task Force (IETF)                          D. Black
Request for Comments: 5663                                   S. Fridella
Category: Standards Track                                EMC Corporation
ISSN: 2070-1721                                               J. Glasgow
                                                                  Google
                                                            January 2010

                Parallel NFS (pNFS) Block/Volume Layout

Abstract

   Parallel NFS (pNFS) extends Network File Sharing version 4 (NFSv4) to
   allow clients to directly access file data on the storage used by the
   NFSv4 server.  This ability to bypass the server for data access can
   increase both performance and parallelism, but requires additional
   client functionality for data access, some of which is dependent on
   the class of storage used.  The main pNFS operations document
   specifies storage-class-independent extensions to NFS; this document
   specifies the additional extensions (primarily data structures) for
   use of pNFS with block- and volume-based storage.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc5663.

Black, et al.                Standards Track                    [Page 1]
RFC 5663                pNFS Block/Volume Layout            January 2010

Copyright Notice

   Copyright (c) 2010 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Black, et al.                Standards Track                    [Page 2]
RFC 5663                pNFS Block/Volume Layout            January 2010

Table of Contents

   1. Introduction ....................................................4
      1.1. Conventions Used in This Document ..........................4
      1.2. General Definitions ........................................5
      1.3. Code Components Licensing Notice ...........................5
      1.4. XDR Description ............................................5
   2. Block Layout Description ........................................7
      2.1. Background and Architecture ................................7
      2.2. GETDEVICELIST and GETDEVICEINFO ............................9
           2.2.1. Volume Identification ...............................9
           2.2.2. Volume Topology ....................................10
           2.2.3. GETDEVICELIST and GETDEVICEINFO deviceid4 ..........12
      2.3. Data Structures: Extents and Extent Lists .................12
           2.3.1. Layout Requests and Extent Lists ...................15
           2.3.2. Layout Commits .....................................16
           2.3.3. Layout Returns .....................................16
           2.3.4. Client Copy-on-Write Processing ....................17
           2.3.5. Extents are Permissions ............................18
           2.3.6. End-of-file Processing .............................20
           2.3.7. Layout Hints .......................................20
           2.3.8. Client Fencing .....................................21
      2.4. Crash Recovery Issues .....................................23
      2.5. Recalling Resources: CB_RECALL_ANY ........................23
      2.6. Transient and Permanent Errors ............................24
   3. Security Considerations ........................................24
   4. Conclusions ....................................................26
   5. IANA Considerations ............................................26
   6. Acknowledgments ................................................26
   7. References .....................................................27
      7.1. Normative References ......................................27