From mboxrd@z Thu Jan  1 00:00:00 1970
From: Stefan Hajnoczi <stefanha@gmail.com>
Subject: Re: Why QCOW1? (was: [PATCH v2] kvm tool: add QCOW verions 1
 read/write support)
Date: Fri, 15 Apr 2011 11:14:41 +0100
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Cc: Markus Armbruster <armbru@redhat.com>,
	Kevin Wolf <kwolf@redhat.com>,
	Prasad Joshi <prasadjoshi124@gmail.com>, mingo@elte.hu,
	kvm@vger.kernel.org, asias.hejun@gmail.com, gorcunov@gmail.com,
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To: Pekka Enberg <penberg@kernel.org>
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On Fri, Apr 15, 2011 at 7:45 AM, Pekka Enberg <penberg@kernel.org> wrote:
> On Fri, Apr 15, 2011 at 9:41 AM, Markus Armbruster <armbru@redhat.com> wrote:
>> What hasn't been discussed much is the other half of Kevin's remark: why
>> QCOW1?
>
> QCOW1 was simpler to implement as the first non-raw image format.

Why even use a non-raw image format?  The current implementation only
does sparse files, but POSIX sparse raw files gives you the same
feature.

Besides, why not use btrfs or device-mapper instead of doing image
formats, which ultimately duplicate file system and volume management
code in userspace?

Stefan