From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 463C3C433DF for ; Tue, 19 May 2020 09:16:41 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 06B45207C4 for ; Tue, 19 May 2020 09:16:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="BKTID9Zq" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 06B45207C4 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:37326 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jayMa-0005wI-7m for qemu-devel@archiver.kernel.org; Tue, 19 May 2020 05:16:40 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:58044) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jayLr-0005Iw-TY for qemu-devel@nongnu.org; Tue, 19 May 2020 05:15:55 -0400 Received: from us-smtp-2.mimecast.com ([207.211.31.81]:31315 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jayLq-00033S-FV for qemu-devel@nongnu.org; Tue, 19 May 2020 05:15:55 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1589879753; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=ZqdLpLz+y4m53DrgqUU/4tBg3Uy8s+Rjs7H2JFxIvuw=; b=BKTID9ZqbeAll6Ja0psPfpbYy8hUSkTc+U96FPbt57t5nK01fD8WqCGbvnbQzI0HeTGswL 76zICeMPlejqMPmjgMwo5sNwl0+X3CVrZjdUWn66/mXUskhos+CksNs5T/RvWsr9wKSKwP hu+C/TSPpzZw1OGB4xOsKsDZEpJ61mE= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-353-MYvF2OjAO_itDW-dblgPng-1; Tue, 19 May 2020 05:15:49 -0400 X-MC-Unique: MYvF2OjAO_itDW-dblgPng-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 27DEA107ACCD; Tue, 19 May 2020 09:15:48 +0000 (UTC) Received: from linux.fritz.box (ovpn-113-199.ams2.redhat.com [10.36.113.199]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 59AF282A1C; Tue, 19 May 2020 09:15:46 +0000 (UTC) Date: Tue, 19 May 2020 11:15:44 +0200 From: Kevin Wolf To: Tao Xu Subject: Re: Migration with ``drive-mirror`` + NBD will let quorum qcow2 image become larger Message-ID: <20200519091544.GD7652@linux.fritz.box> References: <3b1bbe79-088c-2e65-178f-074ac0f72ec6@intel.com> MIME-Version: 1.0 In-Reply-To: <3b1bbe79-088c-2e65-178f-074ac0f72ec6@intel.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=207.211.31.81; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/19 00:34:39 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_PASS=-0.001 autolearn=_AUTOLEARN X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: John Snow , Zhang Chen , Alberto Garcia , "qemu-devel@nongnu.org" , Max Reitz Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Am 19.05.2020 um 10:32 hat Tao Xu geschrieben: > Hi, > > I am using ``drive-mirror`` + NBD for live storage migration. But I find > that if I use a qcow2 image(virtual size: 10 GiB, disk size: 1.8 GiB) as a > child of quorum, then the destination image become larger(virtual size: 10 > GiB, disk size: 10 GiB). However if I use a qcow2 image directly, then the > destination image(virtual size: 10 GiB, disk size: 1.8 GiB) will be equal to > the source. > > So I am wondering if my usage is wrong or it is expected with > quorum+drive-mirror? This seems to be because the quorum block driver doesn't implement the .bdrv_co_block_status interface, so the mirror block job can't know that some blocks are unallocated/zeroed, but will copy everything. I'm not sure if quorum can even implement this interface because the allocation status in different quorum children may differ and voting might not make sense. But maybe it could return a limited set of flags at least so that the mirror job can get the BDRV_BLOCK_ZERO information if the quorum children agree on it. tl;dr: With quorum + drive-mirror it is currently expected. Kevin