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From: Stefan Hajnoczi <stefanha@gmail.com>
To: Bug 1179219 <1179219@bugs.launchpad.net>
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [Bug 1179219] Re: segfault in alloc_refcount_block
Date: Wed, 15 May 2013 10:45:48 +0200	[thread overview]
Message-ID: <20130515084548.GA23423@stefanha-thinkpad.muc.redhat.com> (raw)
In-Reply-To: <51902923.9030305@interlinx.bc.ca>

On Sun, May 12, 2013 at 11:43:31PM -0000, Brian J. Murrell wrote:
> On 13-05-12 05:14 PM, Michael Tokarev wrote:
> > First, having a single qcow2 file open for read-write access by more
> > than one process in unsupported.
> 
> But I don't, if I understand how qcow2 snapshots work.  Let me apologize
> if I was not clear.  Each of the VMs have their own snapshot of the
> common "origin" qcow2 disk.  If I understand correctly in such a
> configuration, only one VM has each snapshot qcow2 open for read-write
> access and they all have the "origin" open read-only, is that correct?
> Surely that must be supported, yes?

$ qemu-img create -f qcow2 -b template.img vm001.qcow2
$ qemu-img create -f qcow2 -b template.img vm002.qcow2
$ qemu-img create -f qcow2 -b template.img vm003.qcow2
$ ...launch vm001-vm002...

This is safe.  The template.img backing file is open read-only.

Did you do anything else?

Stefan

  reply	other threads:[~2013-05-15  8:45 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-05-12 13:59 [Qemu-devel] [Bug 1179219] [NEW] segfault in alloc_refcount_block Brian J. Murrell
2013-05-12 21:14 ` [Qemu-devel] [Bug 1179219] " Michael Tokarev
2013-05-12 23:43   ` Brian J. Murrell
2013-05-15  8:45     ` Stefan Hajnoczi [this message]
2013-05-15 11:07       ` Brian J. Murrell

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