NFS version 4.0 for FreeBSD-CURRENT

[Rick Macklem]

On Sun, 15 Mar 2009, Alfred Perlstein wrote:

>
> I think it wise to look at 4.1 and scoping that out before taking
> the time to integrate this to gain an understanding of:
NFSv4.1 is still way out there. It hasn't reached RFC stage yet and
vendors are only testing bits and pieces of it. (The current draft
of the "minor" revision is over 500 pages.)

All the code vendors are currently shipping is running 4.0.

>
> 1) what it would take to get to 4.1?
A lot. A required feature is something for handling RPC transport
called sessions. One guy has been looking at doing sessions for
FreeBSD (hopefully integrated with Doug Rabson's new RPC code),
but I have no idea if he has made any progress.

> 2) how we would interoperate with other machines until we
> get 4.1 (is everyone doing 4.0 or 4.1?).  When will 4.1 become
> the defacto standard (is it already?)?
Systems should still support 4.0 for a long time. I have no idea
when 4.1 will become a defacto standard, but I'd guess years.
(For 4.0, the RFC is dated 2003 and the Linux implementation of
4.0 is still listed as experimental, I believe. 4.0 shipped with
Solaris10, which was the first production quality implementation,
imho. Apple only shipped an incomplete, non-usable 4.0 with Leopard. 
I think that gives you some idea how long it has taken to
get from RFC to shipping. 4.1 is almost an RFC, but not quite yet.)

> 3) trade-off between taking the 4.0 code or how we can
> get 4.1 first before integration.  This is important because
> the bug reports on 4.0 can swamp someone and prevent new feature
> development (4.1).
>
> You know more about it than most of us, so can you take some time
> to look at 4.1 and give some guestimates so we can gauge what to
> do next?
>
I've tried reading the drafts and got swamped. Honestly, I think a
4.1 implementation would take man years of effort and is beyond
what I am capable of.

Once you have sessions (non trivial, from what I saw), pNFS is what
everyone gets excited about, but it's a major project. To do a server
requires back end server<->server protocols that aren't spelled out
by the draft. A client side of pNFS needs to know how to handle the
various layout schemes (there are 2 other drafts beyond the 500+
page document for 2 other schemes than the most basic whole file one).

> Again, this is really cool and I apologize if 4.1 is something far
> out on the horizon, I just am approaching this from an integration
> perspective, not as an authority on NFSv4 standardization process.
>
> If the case is 4.1 is some number of years out, then I think my
> answer is "let's get this in ASAP!", otherwise we should think
> about it.
>
Yes, I think 4.1 is some years away.

rick