From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:55121) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UcC6e-0006VD-NU for qemu-devel@nongnu.org; Tue, 14 May 2013 06:05:18 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UcC6c-0001pS-LU for qemu-devel@nongnu.org; Tue, 14 May 2013 06:05:16 -0400 Received: from mx1.redhat.com ([209.132.183.28]:2156) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UcC6c-0001pG-Du for qemu-devel@nongnu.org; Tue, 14 May 2013 06:05:14 -0400 Message-ID: <51920C30.4050407@redhat.com> Date: Tue, 14 May 2013 12:04:32 +0200 From: Paolo Bonzini MIME-Version: 1.0 References: <20130514085046.GA2556@dhcp-200-207.str.redhat.com> In-Reply-To: <20130514085046.GA2556@dhcp-200-207.str.redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [RFC] block-trace Low Level Command Supporting Disk Introspection List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Kevin Wolf Cc: Wolfgang Richter , qemu-devel , stefanha Il 14/05/2013 10:50, Kevin Wolf ha scritto: > Or, to translate it into our existing terminology, drive-mirror > implements a passive mirror, you're proposing an active one (which we > do want to have). > > With an active mirror, we'll want to have another choice: The mirror can > be synchronous (guest writes only complete after the mirrored write has > completed) or asynchronous (completion is based only on the original > image). It should be easy enough to support both once an active mirror > exists. Right, I'm waiting for Stefan's block-backup to give me the "right" hooks for the active mirror. The bulk phase will always be passive, but an active-asynchronous mirror has some interesting properties and it makes sense to implement it. Paolo