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From: Stefan Hajnoczi <stefanha@gmail.com>
To: Tomer Margalit <tomermargalit@gmail.com>
Cc: scipioenterprises@yahoo.com, "Zaidenberg,
	Nezer" <Nezer.Zaidenberg@edfenergy.com>,
	qemu-devel@nongnu.org, Nezer Zaidenberg <nzaidenberg@mac.com>,
	Yoshiaki Tamura <tamura.yoshiaki@lab.ntt.co.jp>
Subject: Re: [Qemu-devel] Asynchronously Mirroring a Virtual Machine
Date: Thu, 23 Dec 2010 02:34:46 +0000	[thread overview]
Message-ID: <AANLkTimqpEQS0G_ZFg0uF6wFvpxWs3M4VytNv+aVuhaD@mail.gmail.com> (raw)
In-Reply-To: <AANLkTimTAXQQu2gMpX2+=4yeBHWphxybhHWL36SiZi3k@mail.gmail.com>

On Wed, Dec 22, 2010 at 12:43 PM, Tomer Margalit
<tomermargalit@gmail.com> wrote:
> What I would like to add to it is the ability to asynchronously mirror a
> (QEMU) VM as well, so that if the primary site crashes, the VM can be
> restored (to the last stable point) immediately.
> Since I want it to be as general as possible, I will not rely on my mirror,
> but only on there being a virtual block device that is mirroring me (and
> that has consistent writes (that is, if write A succeeded, and afterwards
> write B succeeded, then if B is on the secondary site, then A must be there
> too)), and that there is some kind of marking mechanism (so that I can mark
> the last consistent state).
> The reason I want to do this using QEMU is that it has live migration -
> which is almost what I need.
> Right now my plan is to treat the memory as a file, and put it and all the
> vm images on the same mirroring block device.

Have you looked at Kemari for KVM (try searching qemu-devel)?  It
builds a fault tolerance mechanism on top of live migration.  Memory,
disk, and network changes are sent to a secondary machine which
passively tracks the state of the VM.  You can fail over to the last
completed transaction state.  Sounds similar to what you want to do.

Stefan

  reply	other threads:[~2010-12-23  2:34 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-12-22 12:43 [Qemu-devel] Asynchronously Mirroring a Virtual Machine Tomer Margalit
2010-12-23  2:34 ` Stefan Hajnoczi [this message]
2010-12-23 17:34   ` Tomer Margalit
2010-12-23 23:44     ` Stefan Hajnoczi

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