From: Paolo Bonzini <pbonzini@redhat.com>
To: Kevin Wolf <kwolf@redhat.com>
Cc: "Stefan Hajnoczi" <stefanha@gmail.com>,
"benoit canet" <benoit.canet@gmail.com>,
"Benoît Canet" <benoit@irqsave.net>,
qemu-devel@nongnu.org, stefanha@linux.vnet.ibm.com
Subject: Re: [Qemu-devel] [PATCH V4 0/3] Block migration if any of the block device is busy
Date: Tue, 24 Jul 2012 07:12:25 -0400 (EDT) [thread overview]
Message-ID: <1349977101.1142289.1343128345560.JavaMail.root@redhat.com> (raw)
In-Reply-To: <500E76C4.3060207@redhat.com>
> > Hmm...maybe this is a policy decision. I figure if you are running
> > image streaming and try to migrate, chances are you're migration
> > will break on the destination host because you were trying to do
> > pre-copy storage migration and never finished.
Streaming is post-copy, and can be interrupted every time you want.
Mirroring is pre-copy. That's another story, but even then the way
to "emulate" migrate -b/-i (and make it much more efficient, as you can
see from the last few patches I just posted) is exactly to run mirroring
in parallel to RAM migration. This is relatively difficult to do by hand
(though I'd like to improve it in 1.3 if only to get rid of block-migration.c)
and requires giving the user a considerable amount of rope, but it is doable.
So, thinking about it a bit more, this patch looks like a good idea in principle,
but actually it is counterproductive.
Paolo
prev parent reply other threads:[~2012-07-24 11:12 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-23 14:22 [Qemu-devel] [PATCH V4 0/3] Block migration if any of the block device is busy benoit.canet
2012-07-23 14:22 ` [Qemu-devel] [PATCH V4 1/3] block: Add bdrv_are_busy() benoit.canet
2012-07-23 17:15 ` Luiz Capitulino
2012-07-24 10:10 ` Benoît Canet
2012-07-24 12:55 ` Luiz Capitulino
2012-07-24 13:29 ` Kevin Wolf
2012-07-24 14:37 ` Benoît Canet
2012-07-24 14:42 ` Kevin Wolf
2012-07-23 14:22 ` [Qemu-devel] [PATCH V4 2/3] qerror: Add error telling that block dev usage prevents migration benoit.canet
2012-07-23 17:09 ` Luiz Capitulino
2012-07-23 14:23 ` [Qemu-devel] [PATCH V4 3/3] migration: block migration when any of the block device is busy benoit.canet
2012-07-23 14:58 ` [Qemu-devel] [PATCH V4 0/3] Block migration if " Stefan Hajnoczi
2012-07-24 9:52 ` Kevin Wolf
2012-07-24 10:04 ` Stefan Hajnoczi
2012-07-24 10:19 ` Kevin Wolf
2012-07-24 11:12 ` Paolo Bonzini [this message]
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