Subject: [nfsv4] Stable Storage definition in NFSv4.1

From: "Mike Eisler" <[email-masked]>
Date: Tue, 2 Dec 2008 20:11:33 -0800 (PST)

The Last Call produced a comment that stated that the Stable Storage
definition wasn't really a definition. Here are proposed diffs:

 <t hangText="Stable Storage">
!           NFSv4.1 servers must be able to recover without data
            loss from multiple power failures (including cascading
            power failures, that is, several power failures in quick
!           succession), operating system failures, and hardware
            failure of components other than the storage medium itself
!           (for example, disk, nonvolatile RAM).
          <vspace blankLines='1' />
            Some examples of stable storage that are allowable for an
            NFS server include:
--- 220,232 ----
            each connection might be associable with the same session.
          </t>
          <t hangText="Stable Storage">
!           Stable storage is storage from which data stored by
!           an NFSv4.1 server can be recovered without data
            loss from multiple power failures (including cascading
            power failures, that is, several power failures in quick
!           succession), operating system failures, and/or hardware
            failure of components other than the storage medium itself
!           (such as disk, nonvolatile RAM, flash memory, etc.).
          <vspace blankLines='1' />
            Some examples of stable storage that are allowable for an

-- 
Mike Eisler, Senior Technical Director, NetApp, 719 599 9026,
http://blogs.netapp.com/eislers_nfs_blog/

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---

From: [email-masked]
Date: Wed, 3 Dec 2008 20:12:54 -0500

On further thought, I would make three edits:
- "loss from multiple power failures" ->
	"loss after multiple power failures"
- "failure of components other than the storage medium itself" ->
	"failure of components other than the stable storage
	medium and associated interface"
- "(such as disk, nonvolatile RAM, flash memory, etc.)" ->
	"Examples of stable storage media include disk and flash
	drives, nonvolatile RAM and flash memory."

The result is:
    Stable storage is storage from which data stored by
    an NFSv4.1 server can be recovered without data
    loss after multiple power failures (including cascading
    power failures, that is, several power failures in quick
    succession), operating system failures, and/or hardware
    failure of components other than the stable storage medium
    and associated interface.  Examples of stable storage media
    include disk and flash drives, nonvolatile RAM and flash
    memory.

Thanks,
--David

> -----Original Message-----
> From: [email-masked] [mailto:[email-masked]] 
> On Behalf Of Mike Eisler
> Sent: Tuesday, December 02, 2008 11:12 PM
> To: [email-masked]
> Subject: [nfsv4] Stable Storage definition in NFSv4.1
>

---

From: Robert Gordon <[email-masked]>
Date: Wed, 3 Dec 2008 19:25:30 -0600

>    include disk and flash drives, nonvolatile RAM and flash

Examples of stable storage media include disk, flash drives,
nonvolatile RAM and flash memory.

Robert.

---

From: "Mike Eisler" <[email-masked]>
Date: Wed, 3 Dec 2008 22:12:25 -0800 (PST)

There's a problem with your result.

It ignores the bullet list that follows.

Taken together it is:

 Some examples of stable storage that are allowable for an
          NFS server include:
          <list style='numbers'>
             <t>
               Media commit of data, that is, the modified data has
               been successfully written to the disk media, for
               example, the disk platter.
             </t>
             <t>
               An immediate reply disk drive with battery-backed on-
               drive intermediate storage or uninterruptible power
               system (UPS).
             </t>
             <t>
               Server commit of data with battery-backed intermediate
               storage and recovery software.
             </t>
             <t>
               Cache commit with uninterruptible power system (UPS) and
               recovery software.
             </t>
           </list>

Pasted together it looks odd have two, overlapping lists of examples
of stable storage.

And if the intent was to exclude systems that use UPS and recovery
software, on the eve of the IESG conference call to decide this
specification's fate, I don't even want to go there.

(Nor do I want the SPEC SFS chair to put a contract out on my
life).

Too much change for now.

---

From: [email-masked]
Date: Thu, 4 Dec 2008 10:06:55 -0500

Then we should just delete the "Examples of stable storage
media ..." sentence.

Thanks,
--David

> From: Mike Eisler [mailto:[email-masked]] 
> Sent: Thursday, December 04, 2008 1:12 AM
> To: Black, David; [email-masked]
> Subject: RE: [nfsv4] Stable Storage definition in NFSv4.1
>

---

From: "Noveck, Dave" <[email-masked]>
Date: Thu, 4 Dec 2008 10:34:55 -0500

This only became "Examples of stable storage media" after David's
proposed edits.  The text in draft-26 was

>    Stable Storage  Stable storage is storage from which data stored by
>       an NFSv4.1 server can be recovered without data loss from
multiple
>       power failures (including cascading power failures, that is,
>       several power failures in quick succession), operating system
>       failures, and/or hardware failure of components other than the
>       storage medium itself (such as disk, nonvolatile RAM, flash
>       memory, etc.).

If we make David's change and then delete that sentence the effect will
be to go from the above to:

>       and associated interface.  

So we've gone from "the storage medium itself" to the "the stable
storage medium itself" and that seems to add the sort of confusion that
Mike was worried about with the two lists.

We then add "and associated interface" and there the problem is that
there is no real definition or even examples of what this means or there
has been no discussion of the implications of adding it at this late
date.

Finally, we have dropped the short parenthetical list which gives some
substance to "the storage media itself and it isn't clear why we've done
that.

> specification's fate, I don't even want to go there.

As far as I understand it, these are lists of examples and so do not
exclude anything, so Mike and the company insuring Mike's life (and
those insuring the rest of the editors' lives as well) can relax.

The definition of stable storage in RFC3530 seems fine to me and has not
been a source of problems.  Given that we are publishing now, it seems
to make sense to add some mention of flash memory (but it we didn't, it
would still be valid to use as it is in v4.0 despite the fact it isn't
the example list in RFC3530).

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] 
Sent: Thursday, December 04, 2008 10:07 AM
To: [email-masked]; [email-masked]
Subject: Re: [nfsv4] Stable Storage definition in NFSv4.1

Thanks,
--David

---

From: Spencer Shepler <[email-masked]>
Date: Thu, 4 Dec 2008 09:42:41 -0600

> the example list in RFC3530).

IMO, the RFC3530 definition is sufficient.  Reword the beginning
to make it a definition and leave the rest as is.

Spencer

---

From: "Mike Eisler" <[email-masked]>
Date: Thu, 4 Dec 2008 07:43:05 -0800 (PST)

I've lost track. -27 is posted. Since IESG comments keep trickling in,
and I have to spin a -28 as a result, I suggest a someone send me diffs,
and if they get to me soon, they might make it into -28.

And by diffs, I mean the output of diff -c. Any else, I don't have
time for, unless IESG completely derails this process. In that case, we'll
have infinite time.

---

From: "Noveck, Dave" <[email-masked]>
Date: Thu, 4 Dec 2008 11:50:51 -0500

I'm fine with what is in draft-27.  This has the advantage that the
diff-c is a follows:

<diff-c>
</diff-c>

:-)

-----Original Message-----
From: Spencer Shepler [mailto:[email-masked]] 
Sent: Thursday, December 04, 2008 10:43 AM
To: Noveck, Dave
Cc: [email-masked]; [email-masked]
Subject: Re: [nfsv4] Stable Storage definition in NFSv4.1

Spencer

---

From: "Mike Eisler" <[email-masked]>
Date: Thu, 4 Dec 2008 10:01:35 -0800 (PST)

On Wed, December 3, 2008 10:12 pm, Mike Eisler wrote:
> [...]

Regarding the above, the chair, Don Capo, known to his friends
as Don the Capp (a diminutive of one his favorite methods
for dealing with obstacles), wanted me to issue this
clarifying statement from him:

    First, there is no such thing as the Mafia or Organized Crime.

    Second, there has never been any proof of my involvement in any
    of Mike Eisler's missing family members, nor the spontaneous
    combustion of his family's pets, relatives, or vehicles.
    Mike and I have a good working relationship and a deep
    understanding of each others needs and motivations.
    I believe his feet are securely cemented to achieving a
    positive outcome for everyone concerned.

I am very relieved and reassured to read the Don's remarks, and
very happy to have received Dave Noveck's zero length context diff.
That will give me more time to locate my hammer and chisel.