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Date: Mon, 22 Aug 2011 16:01:08 -0500
From: Anthony Liguori <anthony@codemonkey.ws>
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Subject: Re: [Qemu-devel] Block layer roadmap on wiki
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To: Ryan Harper <ryanh@us.ibm.com>
Cc: Kevin Wolf <kwolf@redhat.com>, Stefan Hajnoczi <stefanha@gmail.com>, qemu-devel <qemu-devel@nongnu.org>, Christoph Hellwig <hch@lst.de>

On 08/22/2011 03:48 PM, Ryan Harper wrote:
> * Stefan Hajnoczi<stefanha@gmail.com>  [2011-08-22 15:32]:
>> We wouldn't rm -rf block/* because we still need qemu-nbd.  It
>> probably makes sense to keep what we have today.  I'm talking more
>> about a shift from writing our own image format to integrating
>> existing storage support.
>
> I think this is a key point.  While I do like the idea of keeping QEMU
> focused on single VM, I think we don't help ourselves by not consuming
> the hypervisor platform services and integrating/exploiting those
> features to make using QEMU easier.

Let's avoid the h-word here as it's not terribly relevant to the discussion.

Configuring block devices is fundamentally a privileged operation.  QEMU 
fundamentally is designed to be useful as an unprivileged user.

That's the trouble with something like LVM.  Only root can create LVM 
snapshots and it's an all-or-nothing security model.

If you want to get QEMU out of the snapshot business, you need a file 
system that's widely available that allows non-privileged users to take 
snapshots of individual files.

Regards,

Anthony Liguori