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NFSv4 migration: Implementation experience and spec issues to resolve
draft-ietf-nfsv4-migration-issues-06

Document type: Active Internet-Draft (nfsv4 WG)
Document stream: IETF
Last updated: 2014-09-10
Intended RFC status: Unknown
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NFSv4                                                     D. Noveck, Ed.
Internet-Draft                                                      Dell
Intended status: Informational                                 P. Shivam
Expires: March 14, 2015                                         C. Lever
                                                                B. Baker
                                                                  ORACLE
                                                      September 10, 2014

 NFSv4 migration: Implementation experience and spec issues to resolve
                  draft-ietf-nfsv4-migration-issues-06

Abstract

   The migration feature of NFSv4 provides for moving responsibility for
   a single filesystem from one server to another, without disruption to
   clients.  Recent implementation experience has shown problems in the
   existing specification for this feature.  This document discusses the
   issues which have arisen, explores the options available for curing
   the issues, and explains the choices made in updating the NFSv4.0 and
   NFSv4.1 specifications, to address migration.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
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   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on March 14, 2015.

Copyright Notice

   Copyright (c) 2014 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

Noveck, et al.           Expires March 14, 2015                 [Page 1]
Internet-Draft              nfsv4-migr-issues             September 2014

   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.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Conventions . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  NFSv4.0 Implementation Experience . . . . . . . . . . . . . .   4
     3.1.  Implementation issues . . . . . . . . . . . . . . . . . .   4
       3.1.1.  Failure to free migrated state on client reboot . . .   4
       3.1.2.  Server reboots resulting in a confused lease
               situation . . . . . . . . . . . . . . . . . . . . . .   5
       3.1.3.  Client complexity issues  . . . . . . . . . . . . . .   6
     3.2.  Sources of Protocol difficulties  . . . . . . . . . . . .   8
       3.2.1.  Issues with nfs_client_id4 generation and use . . . .   8
       3.2.2.  Issues with lease proliferation . . . . . . . . . . .  10
   4.  Issues to be resolved in NFSv4.0  . . . . . . . . . . . . . .  10
     4.1.  Possible changes to nfs_client_id4 client-string  . . . .  10
     4.2.  Possible changes to handle differing nfs_client_id4
           string values . . . . . . . . . . . . . . . . . . . . . .  12
     4.3.  Possible changes to add a new operation . . . . . . . . .  12
     4.4.  Other issues within migration-state sections  . . . . . .  12
     4.5.  Issues within other sections  . . . . . . . . . . . . . .  13
   5.  Proposed resolution of NFSv4.0 protocol difficulties  . . . .  13
     5.1.  Proposed changes: nfs_client_id4 client-string  . . . . .  14
     5.2.  Proposed changes: merged (vs. synchronized) leases  . . .  14
     5.3.  Other proposed changes to migration-state sections  . . .  16
       5.3.1.  Proposed changes: Client ID migration . . . . . . . .  16
       5.3.2.  Proposed changes: Callback re-establishment . . . . .  17
       5.3.3.  Proposed changes: NFS4ERR_LEASE_MOVED rework  . . . .  17
     5.4.  Proposed changes to other sections  . . . . . . . . . . .  17
       5.4.1.  Proposed changes: callback update . . . . . . . . . .  17
       5.4.2.  Proposed changes: clientid4 handling  . . . . . . . .  18
       5.4.3.  Proposed changes: NFS4ERR_CLID_INUSE  . . . . . . . .  19
   6.  Results of proposed changes for NFSv4.0 . . . . . . . . . . .  20

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