From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:35909) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RumwK-00056Q-Oz for qemu-devel@nongnu.org; Tue, 07 Feb 2012 10:26:49 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1RumwG-0001fL-1L for qemu-devel@nongnu.org; Tue, 07 Feb 2012 10:26:40 -0500 Received: from mx1.redhat.com ([209.132.183.28]:39220) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RumwF-0001f2-IY for qemu-devel@nongnu.org; Tue, 07 Feb 2012 10:26:35 -0500 Message-ID: <4F313AE7.3050104@redhat.com> Date: Tue, 07 Feb 2012 15:53:27 +0100 From: Kevin Wolf MIME-Version: 1.0 References: <73865e0ce364c40e0eb65ec6b22b819d@mail.gmail.com> <4F31153E.9010205@codemonkey.ws> <4F311839.9030709@redhat.com> <4F311BBA.8000708@codemonkey.ws> <4F312FD3.5020206@zerto.com> <4F3137DB.1040503@redhat.com> In-Reply-To: <4F3137DB.1040503@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [RFC PATCH] replication agent module List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini Cc: =?UTF-8?B?16rXldee16gg15HXnyDXkNeV16g=?= , Ori Mamluk , =?UTF-8?B?16LXldeT15Mg16fXk9ed?= , dlaor@redhat.com, qemu-devel@nongnu.org Am 07.02.2012 15:40, schrieb Paolo Bonzini: > On 02/07/2012 03:06 PM, Ori Mamluk wrote: >> The main issue about it is that the Rephub also needs the other >> direction - to read the protected volume. I get the feeling that with >> live block copy and NBD there's probably something that might fit >> this need, no? > > Yes, with two NBD sockets you could do it. But would you use both at > the same time? I would have thought that either the rephub is streaming > from the protected volume, or QEMU is streaming to the rephub. > > The current streaming code in QEMU only deals with the former. > Streaming to a remote server would not be supported. Eventually we'll want to have it. We have been discussing about a mirror block driver more than once. I think the same thing could be reused for both replication and pre-copy live block migration. You would probably have some flags that describe differences in the detail (e.g. whether to wait for the mirrored write or not), but they should be relatively small. Kevin