From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759165Ab3BMAAT (ORCPT ); Tue, 12 Feb 2013 19:00:19 -0500 Received: from mail.avalus.com ([89.16.176.221]:51385 "EHLO mail.avalus.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757805Ab3BMAAQ convert rfc822-to-8bit (ORCPT ); Tue, 12 Feb 2013 19:00:16 -0500 Subject: Re: [PATCH 1/3] nbd: support FLUSH requests Mime-Version: 1.0 (Apple Message framework v1085) Content-Type: text/plain; charset=us-ascii From: Alex Bligh In-Reply-To: <511A8491.5030407@redhat.com> Date: Wed, 13 Feb 2013 00:00:13 +0000 Cc: Alex Bligh , linux-kernel@vger.kernel.org, nbd-general@lists.sf.net, Paul Clements , Andrew Morton Content-Transfer-Encoding: 8BIT Message-Id: <7412A1BC-0383-4539-BCCB-D14FB4206E1B@alex.org.uk> References: <1360685171-3792-1-git-send-email-pbonzini@redhat.com> <1360685171-3792-2-git-send-email-pbonzini@redhat.com> <115932E2-48BE-406E-9E75-61D12EB5937A@alex.org.uk> <511A8491.5030407@redhat.com> To: Paolo Bonzini X-Mailer: Apple Mail (2.1085) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Paolo, On 12 Feb 2013, at 18:06, Paolo Bonzini wrote: > Il 12/02/2013 18:37, Alex Bligh ha scritto: >> For my education, why remove the FUA stuff? > > Because I had no way to test it. I think my mods to the official NBD code support FUA (albeit not very efficiently) >>>>>> Hmmm... the underlying storage could be md/dm RAIDs in which case FUA >>>>>> should be cheaper than FLUSH. >>>> >>>> If someone ever wrote a virtio-blk backend that sits directly ontop >>>> of the Linux block layer that would be true. >> In this case we don't know what the backend is sitting on top of >> a-priori. It might be the current nbd server code, but it might >> not be. > > Do you know of any other NBD server than the "official" one and qemu-nbd? Yes. I know one well (but it's not open source). NBD seems to be the 'goto protocol' for writing distributed block store drivers in user space. -- Alex Bligh