Using Remote Invalidation With RPC-Over-RDMA Transports
draft-cel-nfsv4-reminv-design-06

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Network File System Version 4                                   C. Lever
Internet-Draft                                                    Oracle
Intended status: Informational                             July 17, 2017
Expires: January 18, 2018

        Using Remote Invalidation With RPC-Over-RDMA Transports
                    draft-cel-nfsv4-reminv-design-06

Abstract

   Remote Invalidation relieves RDMA responders of some of the burden of
   preparing memory to be accessed remotely, thus reducing the latency
   of RDMA Read and Write operations.  This document considers how to
   introduce generic support for Remote Invalidation to RPC-over-RDMA
   transport protocols.

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Lever                   Expires January 18, 2018                [Page 1]
Internet-Draft      RPC-over-RDMA Remote Invalidation          July 2017

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Requirements Language . . . . . . . . . . . . . . . . . . . .   4
   3.  General Requirements  . . . . . . . . . . . . . . . . . . . .   4
     3.1.  Memory Management Extensions  . . . . . . . . . . . . . .   4
     3.2.  Registration Types  . . . . . . . . . . . . . . . . . . .   4
     3.3.  Selecting STags to Invalidate Remotely  . . . . . . . . .   5
     3.4.  Future Enhancements . . . . . . . . . . . . . . . . . . .   6
   4.  Remote Invalidation in Operation  . . . . . . . . . . . . . .   6
     4.1.  Determining Remote Invalidation Support Status  . . . . .   7
     4.2.  Selection of Which STag to Invalidate Remotely  . . . . .   8
     4.3.  Reverse-Direction Operation . . . . . . . . . . . . . . .   8
   5.  Protocol Elements . . . . . . . . . . . . . . . . . . . . . .   9
     5.1.  Per Protocol Version Remote Invalidation  . . . . . . . .   9
     5.2.  Per Connection Remote Invalidation  . . . . . . . . . . .   9
     5.3.  Fixed Protocol Remote Invalidation  . . . . . . . . . . .  10
     5.4.  Per RPC Remote Invalidation (Single STag) . . . . . . . .  11
     5.5.  Per RPC Remote Invalidation (Multiple STags)  . . . . . .  12
     5.6.  Inter-RPC Remote Invalidation . . . . . . . . . . . . . .  13
   6.  Recommendations . . . . . . . . . . . . . . . . . . . . . . .  13
     6.1.  General Considerations  . . . . . . . . . . . . . . . . .  13
     6.2.  Analysis And Discussion . . . . . . . . . . . . . . . . .  14
     6.3.  Example Remote Invalidation Protocol  . . . . . . . . . .  15
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  16
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  17
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  17
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .  17
     9.2.  Informative References  . . . . . . . . . . . . . . . . .  18
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .  18
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  18

1.  Introduction

   Like other RDMA-enabled storage protocols, RPC-over-RDMA version 1
   employs a Read-Write transfer model when using explicit RDMA
   operations to transfer data [RFC8166].  This means an RPC-over-RDMA
   requester exposes regions of its memory to an RPC-over-RDMA
   responder.  The responder then uses RDMA Read and Write operations to
   transfer bulk data payloads.

   In preparation for a bulk data transfer, a requester asks its RNIC to
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