From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=45857 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1OGVRq-0001J0-Rr for qemu-devel@nongnu.org; Mon, 24 May 2010 07:03:56 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1OGVRm-0002Cm-Lr for qemu-devel@nongnu.org; Mon, 24 May 2010 07:03:54 -0400 Received: from mx1.redhat.com ([209.132.183.28]:2009) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1OGVRm-0002Cb-93 for qemu-devel@nongnu.org; Mon, 24 May 2010 07:03:50 -0400 Message-ID: <4BFA5D07.8030309@redhat.com> Date: Mon, 24 May 2010 14:03:35 +0300 From: Avi Kivity MIME-Version: 1.0 Subject: Re: [Qemu-devel] [RFC PATCH 1/1] ceph/rbd block driver for qemu-kvm References: <20100519192222.GD61706@ncolin.muc.de> <4BF5A9D2.5080609@codemonkey.ws> <4BF91937.2070801@redhat.com> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Stefan Hajnoczi Cc: kvm@vger.kernel.org, qemu-devel@nongnu.org, Blue Swirl , ceph-devel@vger.kernel.org, Christian Brunner On 05/24/2010 11:27 AM, Stefan Hajnoczi wrote: > On Sun, May 23, 2010 at 1:01 PM, Avi Kivity wrote: > >> On 05/21/2010 12:29 AM, Anthony Liguori wrote: >> >>> I'd be more interested in enabling people to build these types of storage >>> systems without touching qemu. >>> >>> Both sheepdog and ceph ultimately transmit I/O over a socket to a central >>> daemon, right? >>> >> That incurs an extra copy. >> > Besides a shared memory approach, I wonder if the splice() family of > syscalls could be used to send/receive data through a storage daemon > without the daemon looking at or copying the data? > Excellent idea. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic.