Parallel NFS (pNFS) Small Computer System Interface (SCSI) Layout
RFC 8154
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Type |
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RFC - Proposed Standard
(May 2017; No errata)
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Author |
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Christoph Hellwig
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Last updated |
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2017-05-02
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IETF
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plain text
html
pdf
htmlized
bibtex
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Reviews |
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WG state
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Submitted to IESG for Publication
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Document shepherd |
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Spencer Shepler
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Shepherd write-up |
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Show
(last changed 2016-05-09)
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| IESG |
IESG state |
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RFC 8154 (Proposed Standard)
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Consensus Boilerplate |
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Yes
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Telechat date |
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Responsible AD |
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Spencer Dawkins
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Send notices to |
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"Spencer Shepler" <spencer.shepler@gmail.com>
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| IANA |
IANA review state |
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Version Changed - Review Needed
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IANA action state |
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RFC-Ed-Ack
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Internet Engineering Task Force (IETF) C. Hellwig
Request for Comments: 8154 May 2017
Category: Standards Track
ISSN: 2070-1721
Parallel NFS (pNFS) Small Computer System Interface (SCSI) Layout
Abstract
The Parallel Network File System (pNFS) allows a separation between
the metadata (onto a metadata server) and data (onto a storage
device) for a file. The Small Computer System Interface (SCSI)
layout type is defined in this document as an extension to pNFS to
allow the use of SCSI-based block storage devices.
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
http://www.rfc-editor.org/info/rfc8154.
Copyright Notice
Copyright (c) 2017 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.
Hellwig Standards Track [Page 1]
RFC 8154 pNFS SCSI Layout May 2017
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Conventions Used in This Document . . . . . . . . . . . . 4
1.2. General Definitions . . . . . . . . . . . . . . . . . . . 4
1.3. Code Components Licensing Notice . . . . . . . . . . . . 5
1.4. XDR Description . . . . . . . . . . . . . . . . . . . . . 5
2. SCSI Layout Description . . . . . . . . . . . . . . . . . . . 7
2.1. Background and Architecture . . . . . . . . . . . . . . . 7
2.2. layouttype4 . . . . . . . . . . . . . . . . . . . . . . . 8
2.3. GETDEVICEINFO . . . . . . . . . . . . . . . . . . . . . . 8
2.3.1. Volume Identification . . . . . . . . . . . . . . . . 8
2.3.2. Volume Topology . . . . . . . . . . . . . . . . . . . 10
2.4. Data Structures: Extents and Extent Lists . . . . . . . . 12
2.4.1. Layout Requests and Extent Lists . . . . . . . . . . 15
2.4.2. Layout Commits . . . . . . . . . . . . . . . . . . . 16
2.4.3. Layout Returns . . . . . . . . . . . . . . . . . . . 17
2.4.4. Layout Revocation . . . . . . . . . . . . . . . . . . 17
2.4.5. Client Copy-on-Write Processing . . . . . . . . . . . 17
2.4.6. Extents Are Permissions . . . . . . . . . . . . . . . 18
2.4.7. Partial-Block Updates . . . . . . . . . . . . . . . . 19
2.4.8. End-of-File Processing . . . . . . . . . . . . . . . 20
2.4.9. Layout Hints . . . . . . . . . . . . . . . . . . . . 20
2.4.10. Client Fencing . . . . . . . . . . . . . . . . . . . 21
2.5. Crash Recovery Issues . . . . . . . . . . . . . . . . . . 22
2.6. Recalling Resources: CB_RECALL_ANY . . . . . . . . . . . 23
2.7. Transient and Permanent Errors . . . . . . . . . . . . . 23
2.8. Volatile Write Caches . . . . . . . . . . . . . . . . . . 24
3. Enforcing NFSv4 Semantics . . . . . . . . . . . . . . . . . . 24
3.1. Use of Open Stateids . . . . . . . . . . . . . . . . . . 25
3.2. Enforcing Security Restrictions . . . . . . . . . . . . . 26
3.3. Enforcing Locking Restrictions . . . . . . . . . . . . . 26
4. Security Considerations . . . . . . . . . . . . . . . . . . . 27
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 28
6. Normative References . . . . . . . . . . . . . . . . . . . . 28
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 29
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 30
Hellwig Standards Track [Page 2]
RFC 8154 pNFS SCSI Layout May 2017
1. Introduction
Figure 1 shows the overall architecture of a Parallel NFS (pNFS)
system:
+-----------+
|+-----------+ +-----------+
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