Re: [nfsv4] AD Evaluation of draft-ietf-nfsv4-layout-types-08

[Spencer Dawkins at IETF <[e-mail]>]

I looked at -09, and it seems quite reasonable. Thanks for your help during
AD Evaluation.

Mr. Spencer (S), are we ready for Last Call?

Spencer (D)

On Tue, Feb 6, 2018 at 11:38 AM, David Noveck <[e-mail]> wrote:

> > > I found myself wondering "unique within what scope?”
>
>
> > The server and stateid type.
>
> For v4.1, it's actually unique within the scope of a particlar
> client-server pair as repeented by
> a clientid.
>
> Section 8.2 of RFC5661 says:
>
> The server may assign stateids independently for different clients.
>
> A stateid with the same bit pattern for one client may designate an
>
> entirely different set of locks for a different client.  The stateid
>
> is always interpreted with respect to the client ID associated with
>
> the current session.  Stateids apply to all sessions associated with
>
> the given client ID, and the client may use a stateid obtained from
>
> one session on another session associated with the same client ID.
>
>
>
> On Mon, Feb 5, 2018 at 6:00 PM, Thomas Haynes <[e-mail]>
> wrote:
>
>>
>>
>> > On Feb 5, 2018, at 1:52 PM, Spencer Dawkins at IETF <
>> [e-mail]> wrote:
>> >
>> > Dear Authors,
>> >
>> > This draft looks quite clean. NFSv4 drafts usually do.
>> >
>> > I did make some notes during AD Evaluation, and would like to resolve
>> them before requesting IETF Last Call.
>> >
>> > Please let me know what you think.
>> >
>> > Spencer
>> >
>> > In this text from the Abstract,
>> >
>> >   This document defines the requirements which individual pNFS layout
>> >    types need to meet in order to work within the parallel NFS (pNFS)
>> >    framework as defined in RFC5661.  In so doing, it 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 set of requirements has been troublesome
>> >    for those specifying and evaluating new Layout Types.  In this
>> >    regard, this document effectively updates RFC5661.
>> >
>> > I'd suggest dropping "effectively" in the last sentence.
>> >
>>
>> Okay
>>
>>
>> > In this text,
>> >
>> >   The concept of layout type has a central role in the definition and
>> >    implementation of Parallel Network File System (pNFS).  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.
>> >
>> > I'd suggest adding the reference to [RFC5661] at the end of the first
>> sentence, since that's where pNFS is defined (right?). The existing
>> reference to [RFC5661] in the final sentence is fine.
>> >
>>
>>
>> Okay
>>
>>
>> > In this text,
>> >
>> >   As a consequence, new internet drafts (see [FlexFiles] and [Lustre])
>> >    may struggle to meet the requirements to be a pNFS layout type.
>> >
>> > I'd suggest "authors of new specifications" ... "may struggle”.
>>
>> Okay
>>
>>
>> >
>> > I understand that the Terminology section is in alphabetical order, but
>> could you consider whether a different organization might be helpful?
>> "loose coupling" and "tight coupling" seem useful to read together, for
>> instance, but they don't appear on the same page. If you tell me that doing
>> that doesn't seem helpful, I believe you …
>>
>> The only problem is that we might want to make the same change in the
>> Flex Files document.
>>
>> I’ve rearranged them such that the major concepts are grouped together.
>>
>>
>> >
>> > In this text,
>> >
>> >   layout stateid:  is a 128-bit quantity returned by a server that
>> >       uniquely defines the layout state provided by the server for a
>> >       specific layout that describes a layout type and file (see
>> >       Section 12.5.2 of [RFC5661]).
>> >
>> > I found myself wondering "unique within what scope?”
>>
>>
>> The server and stateid type.
>>
>>
>> >
>> > In this text,
>> >
>> > 3.  The Control Protocol
>> >
>> >    A layout type has to meet the requirements that apply to the
>> >    interaction between the metadata server and the storage device such
>> >    that they present to the client a consistent view of stored data and
>> >    lock state (Section 12.2.6 of [RFC5661]).  Particular implementations
>> >    may satisfy these requirements in any manner they choose and the
>> >    mechanism chosen need not be described as a protocol.
>> >
>> > could you give an example of a mechanism that wouldn't be described as
>> a protocol? I can guess, but I'm guessing. The SCSI layout given as an
>> example a bit further down this section is the kind of example I'm thinking
>> about here.
>> >
>>
>> I was actually thinking not of layout types, but of implementations of a
>> Layout Type.
>>
>> The prime example is the NFSv4.1 file layout type as implemented in Data
>> ONTAP by NetApp. The view of stored data, the stateid validation, and the
>> locking state are handled by their clustering software. Do I have a
>> citation for that? Nope.
>>
>>
>>
>> > The security considerations section deflects the reader to the security
>> considerations that appear in layout type specifications, but doesn't
>> provide any specific references to guide the user in finding such
>> specifications. Would it be possible to provide pointers to layout type
>> definition documents, even if there are only one or two that would make
>> sense?
>>
>>
>> While my intent is to say “read the security considerations of each
>> Layout Type spec”, I can present an example.
>>
>> I went with adding this to the end of the paragraph:
>>
>>     For example, in Section 5 of <xref target="RFC5663" />, the lack
>>     of finer-than-physical disk access control necessitates that the
>>     client is delegated the responsibility to enforce the access
>>     provided to them in the layout extent which they were granted by
>>     the metadata server.
>>
>>
>>
>>
>>
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