From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54234) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eF57S-0006Hn-Ps for qemu-devel@nongnu.org; Wed, 15 Nov 2017 16:21:15 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eF57S-0006yI-3H for qemu-devel@nongnu.org; Wed, 15 Nov 2017 16:21:14 -0500 References: <20171113162053.58795-1-vsementsov@virtuozzo.com> From: John Snow Message-ID: <01108daa-fed3-c142-bbd6-0ecc4c8b795d@redhat.com> Date: Wed, 15 Nov 2017 16:20:59 -0500 MIME-Version: 1.0 In-Reply-To: <20171113162053.58795-1-vsementsov@virtuozzo.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH for-2.12 0/4] qmp dirty bitmap API List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Vladimir Sementsov-Ogievskiy , qemu-devel@nongnu.org, qemu-block@nongnu.org Cc: kwolf@redhat.com, famz@redhat.com, armbru@redhat.com, mnestratov@virtuozzo.com, mreitz@redhat.com, nshirokovskiy@virtuozzo.com, stefanha@redhat.com, den@openvz.org, pbonzini@redhat.com On 11/13/2017 11:20 AM, Vladimir Sementsov-Ogievskiy wrote: > Hi all. > > There are three qmp commands, needed to implement external backup API. > > Using these three commands, client may do all needed bitmap management by > hand: > > on backup start we need to do a transaction: > {disable old bitmap, create new bitmap} > > on backup success: > drop old bitmap > > on backup fail: > enable old bitmap > merge new bitmap to old bitmap > drop new bitmap > Can you give me an example of how you expect these commands to be used, and why they're required? I'm a little weary about how error-prone these commands might be and the potential for incorrect usage seems... high. Why do we require them?