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To: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Peng Tao <bergwolf@gmail.com>, bhalevy@tonian.com,
        Boaz Harrosh <bharrosh@panasas.com>, Garth Gibson <garth@panasas.com>,
        Fred Isaman <iisaman@netapp.com>, linux-nfs@vger.kernel.org,
        Matt Benjamin <matt@linuxbox.com>
MIME-Version: 1.0
Subject: Re: [PATCH 0/4] nfs41: allow layoutget at pnfs_do_multiple_writes
Message-ID: <OF5755ED9D.CC1FAA6E-ON88257958.00014359-88257958.0001D4D0@us.ibm.com>
From: Marc Eshel <eshel@almaden.ibm.com>
Date: Tue, 29 Nov 2011 16:20:12 -0800
Content-Type: text/plain; charset="US-ASCII"
Sender: linux-nfs-owner@vger.kernel.org

You ignored my main point, I was talking about the server side, my point 
was that there is nothing to build on on the serve side since the pNFS 
Linux server is not happening.
Marc.


From:
Trond Myklebust <Trond.Myklebust@netapp.com>
To:
Marc Eshel <eshel@almaden.ibm.com>
Cc:
Peng Tao <bergwolf@gmail.com>, bhalevy@tonian.com, Boaz Harrosh 
<bharrosh@panasas.com>, Garth Gibson <garth@panasas.com>, Fred Isaman 
<iisaman@netapp.com>, linux-nfs@vger.kernel.org, Matt Benjamin 
<matt@linuxbox.com>
Date:
11/29/2011 04:08 PM
Subject:
Re: [PATCH 0/4] nfs41: allow layoutget at pnfs_do_multiple_writes


On Tue, 2011-11-29 at 15:49 -0800, Marc Eshel wrote: 
> The only 1 cent that I can add to this argument is that I was led to 
> believe by you and others that Linux kernel don't add functionality on 
the 
> client side that is not supported on the server side. Last time I made 
> this point I was told that it is ok if they are of by a version or two. 
> You made it clear that this is no longer true and that the Linux client 
> and server are now independent of each other. I spent time working on 
the 
> server side believing that the client and server will progress more or 
> less together, disappointed to find out that it is not the case any 
more.
> Marc. 

I don't know how to manage layout segments in a way that meets the pNFS
goals of scalability and performance, and neither you nor the pNFS spec
have told me how to do this.

If IBM wants a client that implements layout segments, then it is _your_
responsibility to: 
     A. Convince me that it is an implementable part of the spec. 
     B. Provide me with an implementation that deals all with the
        concerns that I have.

IOW: nobody has ever promised IBM that the community would do all your
client work for you. EMC, NetApp and Panasas have implemented (most of)
the bits that they cared about; any bits that they haven't implemented
and that you care about are up to you.

-- 
Trond Myklebust
Linux NFS client maintainer

NetApp
Trond.Myklebust@netapp.com
www.netapp.com