From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1N10XG-0004p4-HG for qemu-devel@nongnu.org; Thu, 22 Oct 2009 12:29:10 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1N10XB-0004ju-Ps for qemu-devel@nongnu.org; Thu, 22 Oct 2009 12:29:10 -0400 Received: from [199.232.76.173] (port=45616 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1N10XB-0004jg-Lx for qemu-devel@nongnu.org; Thu, 22 Oct 2009 12:29:05 -0400 Received: from mail-ew0-f221.google.com ([209.85.219.221]:37098) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1N10XB-0000l1-9Q for qemu-devel@nongnu.org; Thu, 22 Oct 2009 12:29:05 -0400 Received: by ewy21 with SMTP id 21so6661876ewy.8 for ; Thu, 22 Oct 2009 09:29:04 -0700 (PDT) Message-ID: <4AE0884B.9060603@codemonkey.ws> Date: Thu, 22 Oct 2009 11:28:59 -0500 From: Anthony Liguori MIME-Version: 1.0 References: <4ADE988B.2070303@lab.ntt.co.jp> <4AE07A7F.8000002@redhat.com> In-Reply-To: <4AE07A7F.8000002@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: [Qemu-devel] Re: [ANNOUNCE] Sheepdog: Distributed Storage System for KVM List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Avi Kivity Cc: linux-fsdevel@vger.kernel.org, kvm@vger.kernel.org, MORITA Kazutaka , qemu-devel@nongnu.org Avi Kivity wrote: > On 10/21/2009 07:13 AM, MORITA Kazutaka wrote: >> Hi everyone, >> >> Sheepdog is a distributed storage system for KVM/QEMU. It provides >> highly available block level storage volumes to VMs like Amazon EBS. >> Sheepdog supports advanced volume management features such as snapshot, >> cloning, and thin provisioning. Sheepdog runs on several tens or >> hundreds >> of nodes, and the architecture is fully symmetric; there is no central >> node such as a meta-data server. > > Very interesting! From a very brief look at the code, it looks like > the sheepdog block format driver is a network client that is able to > access highly available images, yes? > > If so, is it reasonable to compare this to a cluster file system setup > (like GFS) with images as files on this filesystem? The difference > would be that clustering is implemented in userspace in sheepdog, but > in the kernel for a clustering filesystem. I'm still in the process of reading the code, but that's the impression I got too. It made me think that the protocol for qemu to communicate with sheepdog could be a filesystem protocol (like 9p) and sheepdog could expose itself as a synthetic. There are some interesting ramifications to something like that--namely that you could mount sheepdog on localhost and interact with it through the vfs. Very interesting stuff, I'm looking forward to examining more closely. Regards, Anthony Liguori