From: Anthony Liguori <anthony@codemonkey.ws>
To: Avi Kivity <avi@redhat.com>
Cc: Jes.Sorensen@redhat.com, dlaor@redhat.com, qemu-devel@nongnu.org,
Marcelo Tosatti <mtosatti@redhat.com>
Subject: Re: [Qemu-devel] Re: [patch 2/3] Add support for live block copy
Date: Wed, 02 Mar 2011 10:07:53 -0500 [thread overview]
Message-ID: <4D6E5D49.4080101@codemonkey.ws> (raw)
In-Reply-To: <4D6E3F57.8050804@redhat.com>
On 03/02/2011 08:00 AM, Avi Kivity wrote:
> On 03/02/2011 02:39 PM, Anthony Liguori wrote:
>>
>> Here is where your race is:
>>
>> 2. Management sends a switch command
>>
>> 3. QEMU receives switch command
>>
>> 4. QEMU stops doubling IO and switches to the destination
>>
>> 5. QEMU sends acknowledgement of switch command
>>
>> 6. Management receives acknowledge of switch command
>>
>> 7. Management changes internal state definition to reflect the new
>> destination
>>
>> If QEMU or the management tool crashes after step 4 and before step
>> 6, when the management tool restarts QEMU with the source image, data
>> loss will have occurred (and potentially corruption if a flush had
>> happened).
>
> No. After step 2, any qemu restart will be with the destination
> image. If the management tool restarts, it can query the state (or
> just re-issue the switch command, which is idempotent).
Yeah, I think you're right, although I need to think through it a bit more.
Regards,
Anthony Liguori
next prev parent reply other threads:[~2011-03-02 15:10 UTC|newest]
Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-22 17:00 [Qemu-devel] [patch 0/3] live block copy (v2) Marcelo Tosatti
2011-02-22 17:00 ` [Qemu-devel] [patch 1/3] add migration_active function Marcelo Tosatti
2011-02-22 17:00 ` [Qemu-devel] [patch 2/3] Add support for live block copy Marcelo Tosatti
2011-02-22 20:50 ` [Qemu-devel] " Anthony Liguori
2011-02-22 21:07 ` Marcelo Tosatti
2011-02-22 21:11 ` Anthony Liguori
2011-02-22 23:09 ` Marcelo Tosatti
2011-02-22 23:14 ` Anthony Liguori
2011-02-23 13:01 ` Avi Kivity
2011-02-23 14:35 ` Anthony Liguori
2011-02-23 15:31 ` Avi Kivity
2011-02-23 16:01 ` Anthony Liguori
2011-02-23 16:14 ` Avi Kivity
2011-02-23 16:28 ` Anthony Liguori
2011-02-23 17:18 ` Avi Kivity
2011-02-23 20:18 ` Anthony Liguori
2011-02-23 20:44 ` Marcelo Tosatti
2011-02-23 21:41 ` Anthony Liguori
2011-02-24 14:39 ` Marcelo Tosatti
2011-02-24 7:37 ` Markus Armbruster
2011-02-24 8:54 ` Avi Kivity
2011-02-24 15:00 ` Anthony Liguori
2011-02-24 15:22 ` Avi Kivity
2011-02-24 17:58 ` Anthony Liguori
2011-02-27 9:10 ` Avi Kivity
2011-02-27 9:55 ` Dor Laor
2011-02-27 13:49 ` Anthony Liguori
2011-02-27 16:02 ` Dor Laor
2011-02-27 17:25 ` Anthony Liguori
2011-02-28 8:58 ` Dor Laor
2011-02-27 14:00 ` Anthony Liguori
2011-02-27 15:31 ` Avi Kivity
2011-02-27 17:41 ` Anthony Liguori
2011-02-28 8:38 ` Avi Kivity
2011-02-28 12:45 ` Anthony Liguori
2011-02-28 13:21 ` Avi Kivity
2011-02-28 17:33 ` Anthony Liguori
2011-02-28 17:47 ` Avi Kivity
2011-02-28 18:12 ` Anthony Liguori
[not found] ` <4D6CBECF.8090805@redhat.c! om>
[not found] ` <4D6CB556.5060401@redhat.c! om>
2011-03-01 8:59 ` Dor Laor
2011-03-02 12:39 ` Anthony Liguori
2011-03-02 13:00 ` Avi Kivity
2011-03-02 15:07 ` Anthony Liguori [this message]
2011-03-01 9:39 ` Avi Kivity
2011-03-01 15:51 ` Anthony Liguori
2011-03-01 22:27 ` Dor Laor
2011-03-02 16:30 ` Avi Kivity
2011-03-02 21:55 ` Anthony Liguori
2011-02-28 18:56 ` Marcelo Tosatti
2011-03-01 9:45 ` Avi Kivity
2011-02-23 16:17 ` Peter Maydell
2011-02-23 16:30 ` Anthony Liguori
2011-02-24 5:41 ` [Qemu-devel] Unsubsribing James Brown
2011-02-24 10:00 ` Stefan Hajnoczi
2011-02-23 17:26 ` [Qemu-devel] Re: [patch 2/3] Add support for live block copy Markus Armbruster
2011-02-23 20:06 ` Anthony Liguori
2011-02-24 12:15 ` Markus Armbruster
2011-02-25 7:16 ` Stefan Hajnoczi
2011-02-23 17:49 ` Marcelo Tosatti
2011-02-24 8:58 ` Avi Kivity
2011-02-24 15:14 ` Marcelo Tosatti
2011-02-24 15:28 ` Avi Kivity
2011-02-24 16:39 ` Marcelo Tosatti
2011-02-24 17:32 ` Avi Kivity
2011-02-24 17:45 ` Anthony Liguori
2011-02-27 9:22 ` Avi Kivity
2011-02-23 12:46 ` Avi Kivity
2011-02-22 20:50 ` Anthony Liguori
2011-02-22 21:16 ` [Qemu-devel] " Anthony Liguori
2011-02-23 19:06 ` Anthony Liguori
2011-02-26 0:02 ` Marcelo Tosatti
2011-02-26 13:45 ` Anthony Liguori
2011-02-28 19:09 ` Marcelo Tosatti
2011-03-01 2:35 ` Marcelo Tosatti
2011-02-26 15:32 ` Anthony Liguori
2011-02-22 17:00 ` [Qemu-devel] [patch 3/3] do not allow migration if block copy in progress Marcelo Tosatti
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