Re: [nfsv4] I-D Action: draft-talpey-rdma-commit-02.txt

[Chuck Lever III <[e-mail]>]

> On Jan 25, 2023, at 2:22 PM, Tom Talpey <[e-mail]> wrote:
> 
> The RDMA Placement Extensions draft has been revised and updated,
> and it's available for the NFSv4 Working Group to again consider.
> 
> This was previously discussed and conditionally approved as an NFSv4 work item, but the chairs and area director felt that enough time has passed that it warrants a brief discussion to refresh consensus. This is planned for IETF 116 in March. Review and discussion can start now.
> 
> This version revises and updates the text, and incorporates all comments received earlier. The core protocol and its concepts remain unchanged.

I read through this document to get a flavor. A couple of observations/comments follow:

The Requirements Language section needs to be updated to include a reference to RFC 8174. For reference, the most recent version of the RL boilerplate looks like this:

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in
   BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

Section 1 is lengthy and contains considerable repetition.
	• Admittedly, introductions are challenging to write, but the tone of some of the text is somewhat informal and/or not appropriate for a standards document. I leave it to the current author to whittle this section down as needed.
	• Occasionally when "host CPU involvement" is mentioned, it is not clear whether the local or remote CPU is meant.
	• The definition of "Persistence" in Section 1.1 is confusing.
		• Perhaps a short discussion of the terms "persistence" and "durability" (or a mention that they are synonyms) might be appropriate.
		• The URLs in Section 1.1 should appear in the Informative References section, not in Section 1.1. The sentence that contains them appears to be garbled.
	• Is there a purpose for "Global" in the definition of "Global Visibility" (as opposed to "Local Visibility")? A brief discussion of that distinction would help orient readers; or perhaps it is covered elsewhere in the document and I missed it.

Section 3 is marked "INCOMPLETE". What is the plan to complete this section? Is there other remaining significant work planned for this document?

Is there any implementation status to document via an "Implementation Status" section? I would like to see one... or at least an informal report on the mailing list about current implementation plans, as part of the planned IETF 116 discussion of this document.

The third paragraph of "6. Security Considerations" touches on this, but what is the trust relationship between the peers in push mode? How do push mode peers authenticate to each other?


> Document information below. Thanks!
> 
> Tom.
> 
> 
> -------- Forwarded Message --------
> Subject: I-D Action: draft-talpey-rdma-commit-02.txt
> Date: Wed, 25 Jan 2023 10:52:21 -0800
> From: [e-mail]
> Reply-To: [e-mail]
> To: [e-mail]
> 
> 
> A New Internet-Draft is available from the on-line Internet-Drafts directories.
> 
> 
>        Title           : RDMA Extensions for Enhanced Memory Placement
>        Author          : Tom Talpey
>  Filename        : draft-talpey-rdma-commit-02.txt
>  Pages           : 37
>  Date            : 2023-01-25
> 
> Abstract:
>   This document specifies extensions to RDMA (Remote Direct Memory
>   Access) protocols to provide capabilities in support of enhanced
>   remotely-directed data placement on memory-addressable devices,
>   including persistent memory.  The extensions include new operations
>   supporting remote commitment to persistence of remotely-managed
>   buffers, which can provide enhanced guarantees and improve
>   performance for low-latency storage applications, and to the
>   visibility of such buffers in support of remote shared memory
>   semantics.  This document updates RFC 5040 (Remote Direct Memory
>   Access Protocol (RDMAP)) and updates RFC 7306 (RDMA Protocol
>   Extensions).
> 
> 
> 
> The IETF datatracker status page for this draft is:
> https://datatracker.ietf.org/doc/draft-talpey-rdma-commit/
> 
> There is also an htmlized version available at:
> https://datatracker.ietf.org/doc/html/draft-talpey-rdma-commit-02
> 
> A diff from the previous version is available at:
> https://author-tools.ietf.org/iddiff?url2=draft-talpey-rdma-commit-02
> 
> 
> Internet-Drafts are also available by rsync at rsync.ietf.org::internet-drafts
> 
> 
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--
Chuck Lever