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[209.132.180.67]) by mx.google.com with ESMTP id m12si2287465pjq.67.2019.06.14.06.38.28; Fri, 14 Jun 2019 06:38:45 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@toxicpanda-com.20150623.gappssmtp.com header.s=20150623 header.b=RDZZZjUc; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728248AbfFNNiH (ORCPT + 99 others); Fri, 14 Jun 2019 09:38:07 -0400 Received: from mail-qt1-f193.google.com ([209.85.160.193]:34517 "EHLO mail-qt1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728223AbfFNNiH (ORCPT ); Fri, 14 Jun 2019 09:38:07 -0400 Received: by mail-qt1-f193.google.com with SMTP id m29so2483254qtu.1 for ; Fri, 14 Jun 2019 06:38:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=toxicpanda-com.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=5t38AdsOWv2f4Esw1W+MkepSRzr1WITdyAORH+5HjYw=; b=RDZZZjUcgP1IQISh2OS0tjJq7h2lcyaLEZF4ZlCEaiFMBb9xylkmRKTOFdBqzT4CmS pPUNoWCPpe3HFF/pMsbtof/jbvEp5RIksEwku+dWkHcrlYJ26kD9Dqq5vGTtWz2qLZsm VigUHIj4paQ6Tly6gHAio3+6dTylmk0AM/qW0Xa+828w0olfCI3nAOPWG3ZBTFlUUwjr 9ow0YUAkq1hZQxV/aVZ/hWkdJ/YlB0EkCruIxzq+fKMxvsU6C/q0Q9meiBgvgag9IWlF nccl5LY9zCXLLTksQBIci7LGgigiZ7vLU/6wZgWVN3V/czpvgZ2WGFhaN6Pw1JJ3t5FP dI4w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=5t38AdsOWv2f4Esw1W+MkepSRzr1WITdyAORH+5HjYw=; b=A5WNMmmfDMVPT4hHRs2nmO9Jl/ASCaQYw75tuIXb9Jr0nPOUUGydgnh2hFY8KclZ9m bW3R5qOgE4UG26IVNO9btrOVwblZt9B5cQs/ItbA8JlsFuKz+XO+w1EqmMX8NnVGkHfj gS0Qs51x1nmZTYYppiteEjsFUeDmh6pbKBrKxbAqwMi/OGkAD088uv55fjT0pj6d7+BA W1Z/Jcvw8+NtNCQJzh2RSiVN/H1mNBVO/3osmpD0HeZWV97/c7QuNh0rFsZk8Nm0jAxz dyPIrtT8lbkBtoftiSbweBfQewTDfPssDvpu1Lhgw45ePkcRpvh8S6IXFzyyqrVx5N9d h/Qw== X-Gm-Message-State: APjAAAX6YxEhl99FM2vImDtoynFWeOMpbQOoFPiLZUmvA3PvYNEdviq7 pWx1XDZRb1LfCceig28DZHRy5A== X-Received: by 2002:ac8:2fa8:: with SMTP id l37mr78660838qta.358.1560519486142; Fri, 14 Jun 2019 06:38:06 -0700 (PDT) Received: from localhost ([2620:10d:c091:480::a658]) by smtp.gmail.com with ESMTPSA id t67sm1449588qkf.34.2019.06.14.06.38.05 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 14 Jun 2019 06:38:05 -0700 (PDT) Date: Fri, 14 Jun 2019 09:38:04 -0400 From: Josef Bacik To: Wouter Verhelst Cc: Josef Bacik , Roman Stratiienko , linux-kernel@vger.kernel.org, nbd@other.debian.org, Aleksandr Bulyshchenko , linux-block@vger.kernel.org, axboe@kernel.dkn.org Subject: Re: [PATCH 2/2] nbd: add support for nbd as root device Message-ID: <20190614133802.vg3w3sxpid2fpbp4@MacBook-Pro-91.local> References: <20190612163144.18486-1-roman.stratiienko@globallogic.com> <20190612163144.18486-2-roman.stratiienko@globallogic.com> <20190613135241.aghcrrz7rg2au3bw@MacBook-Pro-91.local> <20190613145535.tdesq3y2xy6ycpw7@MacBook-Pro-91.local> <20190614103343.GB11340@grep.be> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190614103343.GB11340@grep.be> User-Agent: NeoMutt/20180716 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 14, 2019 at 12:33:43PM +0200, Wouter Verhelst wrote: > On Thu, Jun 13, 2019 at 10:55:36AM -0400, Josef Bacik wrote: > > Also I mean that there are a bunch of different nbd servers out there. We have > > our own here at Facebook, qemu has one, IIRC there's a ceph one. > > I can't claim to know about the Facebook one of course, but the qemu one > uses the same handshake protocol as anyone else. The ceph ones that I've > seen do too (but there are various implementations of that, so...). > Ah, for some reason I remembered Qemu's being distinctly different. I suppose if most of the main ones people use are using the same handshake protocol that makes it more compelling. But there'd have to be a really good reason why a initramfs isn't viable, and so far I haven't heard a solid reason that's not an option other than "it's hard and we don't want to do it." > > They all have their own connection protocols. The beauty of NBD is > > that it doesn't have to know about that part, it just does the block > > device part, and I'd really rather leave it that way. Thanks, > > Sure. > > OTOH, there is definitely also a benefit to using the same handshake > protocol everywhere, for interoperability reasons. > Sure, Facebook's isn't different because we hate the protocol, we just use Thrift for all of our services, and thus it makes sense for us to use thrift for the client connection stuff to make it easy on all the apps that use disagg. Thanks, Josef