From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:48356) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QrBZ4-00015m-KN for qemu-devel@nongnu.org; Wed, 10 Aug 2011 12:23:31 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1QrBZ3-0005Y0-D6 for qemu-devel@nongnu.org; Wed, 10 Aug 2011 12:23:30 -0400 Received: from mail-pz0-f42.google.com ([209.85.210.42]:32856) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QrBZ3-0005Xq-62 for qemu-devel@nongnu.org; Wed, 10 Aug 2011 12:23:29 -0400 Received: by pzk37 with SMTP id 37so2449380pzk.29 for ; Wed, 10 Aug 2011 09:23:27 -0700 (PDT) Message-ID: <4E42B07C.2090805@codemonkey.ws> Date: Wed, 10 Aug 2011 11:23:24 -0500 From: Anthony Liguori MIME-Version: 1.0 References: <4E3FF6AE.8030004@redhat.com> <4E3FF705.9080009@redhat.com> <4E3FFC7A.3090000@codemonkey.ws> <4E3FFD76.4010804@redhat.com> <4E400C78.1020104@codemonkey.ws> <4E40147E.2080403@redhat.com> <4E401504.7080309@codemonkey.ws> <4E429FE6.4060408@redhat.com> <4E42AABB.3020306@codemonkey.ws> <4E42ACF9.3040101@redhat.com> In-Reply-To: <4E42ACF9.3040101@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v4] XBZRLE delta for live migration of large memory apps List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Avi Kivity Cc: Blue Swirl , Stefan Hajnoczi , "Shribman, Aidan" , qemu-devel Developers On 08/10/2011 11:08 AM, Avi Kivity wrote: > On 08/10/2011 06:58 PM, Anthony Liguori wrote: >>> I don't think we should couple the two features together. >> >> >> ASN.1 is orthogonal to capabilities. >> >> Capabilities are a hard requirement before merging any new type of >> compression algorithm IMO. > > Right now we have capabilties in the form of -help output. > > If -help says > > -no-xzbrle disable xzbrle support > > (or -migration-compression xzbrle=off, or something) that's sufficient > for management tools. This is static, not dynamic. You may attempt to migrate to another host that supports it and then migrate to a second host that doesn't support it after the first migration fails. > > We shouldn't block this feature just because some monitor facility is > not yet implemented. We shouldn't make *any* changes to the migration protocol before we have a feature negotiation capability. I only want to do a hard break of the protocol once. Regards, Anthony Liguori