From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47104) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZuJVR-0001fK-9V for qemu-devel@nongnu.org; Thu, 05 Nov 2015 07:19:06 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZuJVO-00041o-1x for qemu-devel@nongnu.org; Thu, 05 Nov 2015 07:19:05 -0500 Received: from mx1.redhat.com ([209.132.183.28]:33077) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZuJVN-00041k-TC for qemu-devel@nongnu.org; Thu, 05 Nov 2015 07:19:01 -0500 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (Postfix) with ESMTPS id 6545B1306 for ; Thu, 5 Nov 2015 12:19:01 +0000 (UTC) Date: Thu, 5 Nov 2015 12:18:59 +0000 From: "Richard W.M. Jones" Message-ID: <20151105121859.GR29330@redhat.com> References: <20151104163730.GB28428@redhat.com> <20151105071449.GH24893@ad.usersys.redhat.com> <20151105085622.GQ29330@redhat.com> <20151105094601.GA14058@ad.usersys.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20151105094601.GA14058@ad.usersys.redhat.com> Subject: Re: [Qemu-devel] Should 'qemu-img commit' sparsify the backing file? List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Fam Zheng Cc: qemu-devel@nongnu.org On Thu, Nov 05, 2015 at 05:46:01PM +0800, Fam Zheng wrote: > Does virt-sparsify work if there is no file system present (e.g. the disk is > fully filled with zeroes) on the device? It doesn't do anything bad, but it doesn't currently do that. You could do that using: guestfish <