From: Stefan Hajnoczi <stefanha@gmail.com> To: Marcelo Tosatti <mtosatti@redhat.com> Cc: quintela@redhat.com, KVM devel mailing list <kvm@vger.kernel.org>, qemu-devel@nongnu.org, Chris Wright <chrisw@redhat.com>, Kevin Wolf <kwolf@redhat.com> Subject: Re: KVM call agenda for June 28 Date: Wed, 29 Jun 2011 06:32:39 +0100 [thread overview] Message-ID: <BANLkTikA-raTtUtP+iN3oR82y0cxKHjL4w@mail.gmail.com> (raw) In-Reply-To: <20110628194106.GA17443@amt.cnet> On Tue, Jun 28, 2011 at 8:41 PM, Marcelo Tosatti <mtosatti@redhat.com> wrote: > On Tue, Jun 28, 2011 at 02:38:15PM +0100, Stefan Hajnoczi wrote: >> On Mon, Jun 27, 2011 at 3:32 PM, Juan Quintela <quintela@redhat.com> wrote: >> > Please send in any agenda items you are interested in covering. >> >> Live block copy and image streaming: >> * The differences between Marcelo and Kevin's approaches >> * Which approach to choose and who can help implement it > > After more thinking, i dislike the image metadata approach. Management > must carry the information anyway, so its pointless to duplicate it > inside an image format. I agree with you. It would be a significant change for QEMU users to deal with block state files just in case they want to use live block copy/image streaming. Not only would existing management layers need to be updated but also custom management or provisioning scripts. > After the discussion today, i think the internal mechanism and interface > should be different for copy and stream: > > block copy > ---------- > > With backing files: > > 1) base <- sn1 <- sn2 > 2) base <- copy > > Without: > > 1) source > 2) destination > > Copy is only valid after switch has been performed. Same interface and > crash recovery characteristics for all image formats. > > If management wants to support continuation, it must specify > blkcopy:sn2:copy on startup. > > stream > ------ > > 1) base <- remote > 2) base <- remote <- local > 3) base <- local > > "local" image is always valid. Requires backing file support. I agree that the modes of operation are different and we should provide different HMP/QMP APIs for them. Internally I still think they can share code for the source -> destination copy operation. Stefan
WARNING: multiple messages have this Message-ID (diff)
From: Stefan Hajnoczi <stefanha@gmail.com> To: Marcelo Tosatti <mtosatti@redhat.com> Cc: Chris Wright <chrisw@redhat.com>, Kevin Wolf <kwolf@redhat.com>, qemu-devel@nongnu.org, KVM devel mailing list <kvm@vger.kernel.org>, quintela@redhat.com Subject: Re: [Qemu-devel] KVM call agenda for June 28 Date: Wed, 29 Jun 2011 06:32:39 +0100 [thread overview] Message-ID: <BANLkTikA-raTtUtP+iN3oR82y0cxKHjL4w@mail.gmail.com> (raw) In-Reply-To: <20110628194106.GA17443@amt.cnet> On Tue, Jun 28, 2011 at 8:41 PM, Marcelo Tosatti <mtosatti@redhat.com> wrote: > On Tue, Jun 28, 2011 at 02:38:15PM +0100, Stefan Hajnoczi wrote: >> On Mon, Jun 27, 2011 at 3:32 PM, Juan Quintela <quintela@redhat.com> wrote: >> > Please send in any agenda items you are interested in covering. >> >> Live block copy and image streaming: >> * The differences between Marcelo and Kevin's approaches >> * Which approach to choose and who can help implement it > > After more thinking, i dislike the image metadata approach. Management > must carry the information anyway, so its pointless to duplicate it > inside an image format. I agree with you. It would be a significant change for QEMU users to deal with block state files just in case they want to use live block copy/image streaming. Not only would existing management layers need to be updated but also custom management or provisioning scripts. > After the discussion today, i think the internal mechanism and interface > should be different for copy and stream: > > block copy > ---------- > > With backing files: > > 1) base <- sn1 <- sn2 > 2) base <- copy > > Without: > > 1) source > 2) destination > > Copy is only valid after switch has been performed. Same interface and > crash recovery characteristics for all image formats. > > If management wants to support continuation, it must specify > blkcopy:sn2:copy on startup. > > stream > ------ > > 1) base <- remote > 2) base <- remote <- local > 3) base <- local > > "local" image is always valid. Requires backing file support. I agree that the modes of operation are different and we should provide different HMP/QMP APIs for them. Internally I still think they can share code for the source -> destination copy operation. Stefan
next prev parent reply other threads:[~2011-06-29 5:32 UTC|newest] Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top 2011-06-27 14:32 KVM call agenda for June 28 Juan Quintela 2011-06-27 14:32 ` [Qemu-devel] " Juan Quintela 2011-06-28 13:38 ` Stefan Hajnoczi 2011-06-28 13:38 ` [Qemu-devel] " Stefan Hajnoczi 2011-06-28 19:41 ` Marcelo Tosatti 2011-06-28 19:41 ` [Qemu-devel] " Marcelo Tosatti 2011-06-29 5:32 ` Stefan Hajnoczi [this message] 2011-06-29 5:32 ` Stefan Hajnoczi 2011-06-29 7:57 ` Kevin Wolf 2011-06-29 7:57 ` [Qemu-devel] " Kevin Wolf 2011-06-29 10:08 ` Stefan Hajnoczi 2011-06-29 10:08 ` [Qemu-devel] " Stefan Hajnoczi 2011-06-29 15:41 ` Marcelo Tosatti 2011-06-29 15:41 ` [Qemu-devel] " Marcelo Tosatti 2011-06-30 11:48 ` Stefan Hajnoczi 2011-06-30 11:48 ` [Qemu-devel] " Stefan Hajnoczi 2011-06-30 12:39 ` Kevin Wolf 2011-06-30 12:39 ` [Qemu-devel] " Kevin Wolf 2011-06-30 12:54 ` Stefan Hajnoczi 2011-06-30 12:54 ` [Qemu-devel] " Stefan Hajnoczi 2011-06-30 14:36 ` Marcelo Tosatti 2011-06-30 14:36 ` [Qemu-devel] " Marcelo Tosatti 2011-06-30 14:52 ` Kevin Wolf 2011-06-30 14:52 ` [Qemu-devel] " Kevin Wolf 2011-06-30 18:38 ` Marcelo Tosatti 2011-07-05 8:01 ` Dor Laor 2011-07-05 12:40 ` Stefan Hajnoczi 2011-07-05 12:40 ` Stefan Hajnoczi 2011-07-05 12:58 ` Marcelo Tosatti 2011-07-05 12:58 ` Marcelo Tosatti 2011-07-05 13:39 ` Dor Laor 2011-07-05 13:39 ` Dor Laor 2011-07-05 14:29 ` Marcelo Tosatti 2011-07-05 14:29 ` [Qemu-devel] " Marcelo Tosatti 2011-07-05 14:32 ` Marcelo Tosatti 2011-07-05 14:32 ` Marcelo Tosatti 2011-07-05 14:46 ` Kevin Wolf 2011-07-05 14:46 ` Kevin Wolf 2011-07-05 15:04 ` Dor Laor 2011-07-05 15:04 ` Dor Laor 2011-07-05 15:29 ` Marcelo Tosatti 2011-07-05 15:29 ` Marcelo Tosatti 2011-07-05 15:37 ` Stefan Hajnoczi 2011-07-05 15:37 ` Stefan Hajnoczi 2011-07-05 18:18 ` Marcelo Tosatti 2011-07-05 18:18 ` Marcelo Tosatti 2011-07-06 7:48 ` Kevin Wolf 2011-07-06 7:48 ` Kevin Wolf 2011-07-07 15:25 ` Stefan Hajnoczi 2011-07-07 15:25 ` Stefan Hajnoczi 2011-06-28 13:43 ` Anthony Liguori 2011-06-28 13:43 ` Anthony Liguori 2011-06-28 13:48 ` Avi Kivity 2011-06-28 13:48 ` Avi Kivity 2011-06-30 14:10 ` Anthony Liguori
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