From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:37697) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1THGTs-0002av-4v for qemu-devel@nongnu.org; Thu, 27 Sep 2012 11:58:32 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1THGTk-0000F0-BY for qemu-devel@nongnu.org; Thu, 27 Sep 2012 11:58:28 -0400 Received: from mx1.redhat.com ([209.132.183.28]:46519) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1THGTk-0000Ev-26 for qemu-devel@nongnu.org; Thu, 27 Sep 2012 11:58:20 -0400 Message-ID: <50647793.7000106@redhat.com> Date: Thu, 27 Sep 2012 17:58:11 +0200 From: Avi Kivity MIME-Version: 1.0 References: <1348756198-10845-1-git-send-email-benoit@irqsave.net> In-Reply-To: <1348756198-10845-1-git-send-email-benoit@irqsave.net> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [partial RFC 0/2] QCow2 deduplication write mechanism List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: =?UTF-8?B?QmVub8OudCBDYW5ldA==?= Cc: kwolf@redhat.com, pbonzini@redhat.com, qemu-devel@nongnu.org, stefanha@linux.vnet.ibm.com On 09/27/2012 04:29 PM, Beno=C3=AEt Canet wrote: > This patchset introduce a partial implementation of a deduplication mec= hanism > for QCow2. > This patchset layout the disk format changes in the qcow2 spec and > provide a partial implementation of the write mechanisms. >=20 > Albeit being partial this is posted to get an early feedback and > see if things are on track. If I understood correctly, this does cluster-level dedup within a qcow2 image. What is the motivation here? Reduce space usage if a guest copies files internally? Why use cluster granularity? If the guest uses smaller granularity, it will misalign the data wrt cluster boundaries, and deduplication will fai= l. --=20 error compiling committee.c: too many arguments to function