Requirements for Parallel NFS (pNFS) Layout Types
RFC 8434

Document Type RFC - Proposed Standard (August 2018; No errata)
Updates RFC 5661
Last updated 2018-08-24
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Internet Engineering Task Force (IETF)                         T. Haynes
Request for Comments: 8434                                   Hammerspace
Updates: 5661                                                August 2018
Category: Standards Track
ISSN: 2070-1721

           Requirements for Parallel NFS (pNFS) Layout Types

Abstract

   This document defines the requirements that individual Parallel NFS
   (pNFS) layout types need to meet in order to work within the pNFS
   framework as defined in RFC 5661.  In so doing, this document aims to
   clearly distinguish between requirements for pNFS as a whole and
   those specifically directed to the pNFS file layout.  The lack of a
   clear separation between the two sets of requirements has been
   troublesome for those specifying and evaluating new layout types.  In
   this regard, this document updates RFC 5661.

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 7841.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   https://www.rfc-editor.org/info/rfc8434.

Copyright Notice

   Copyright (c) 2018 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
   (https://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.

Haynes                       Standards Track                    [Page 1]
RFC 8434                    pNFS Layout Types                August 2018

Table of Contents

   1. Introduction ....................................................2
   2. Definitions .....................................................3
      2.1. Use of the Terms "Data Server" and "Storage Device" ........5
      2.2. Requirements Language ......................................6
   3. The Control Protocol ............................................6
      3.1. Control Protocol Requirements ..............................8
      3.2. Previously Undocumented Protocol Requirements ..............9
      3.3. Editorial Requirements ....................................10
   4. Specifications of Original Layout Types ........................11
      4.1. File Layout Type ..........................................11
      4.2. Block Layout Type .........................................12
      4.3. Object Layout Type ........................................13
   5. Summary ........................................................14
   6. Security Considerations ........................................15
   7. IANA Considerations ............................................15
   8. References .....................................................16
      8.1. Normative References ......................................16
      8.2. Informative References ....................................16
   Acknowledgments ...................................................17
   Author's Address ..................................................17

1.  Introduction

   The concept of "layout type" has a central role in the definition and
   implementation of Parallel NFS (pNFS) (see [RFC5661]).  Clients and
   servers implementing different layout types behave differently in
   many ways while conforming to the overall pNFS framework defined in
   [RFC5661] and this document.  Layout types may differ as to:

   o  The method used to do I/O operations directed to data storage
      devices.

   o  The requirements for communication between the metadata server
      (MDS) and the storage devices.

   o  The means used to ensure that I/O requests are only processed when
      the client holds an appropriate layout.

   o  The format and interpretation of nominally opaque data fields in
      pNFS-related NFSv4.x data structures.

   Each layout type will define the needed details for its usage in the
   specification for that layout type; layout type specifications are
   always Standards Track RFCs.  Except for the file layout type defined

Haynes                       Standards Track                    [Page 2]
RFC 8434                    pNFS Layout Types                August 2018

   in Section 13 of [RFC5661], existing layout types are defined in
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