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] ` <4D6CB556.5060401@redhat.c! om>
[not found] ` <4D6CBECF.8090805@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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4D6E5D49.4080101@codemonkey.ws \
--to=anthony@codemonkey.ws \
--cc=Jes.Sorensen@redhat.com \
--cc=avi@redhat.com \
--cc=dlaor@redhat.com \
--cc=mtosatti@redhat.com \
--cc=qemu-devel@nongnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.