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From: Marc Bevand <m.bevand@gmail.com>
To: dlaor@redhat.com
Cc: Jamie Lokier <jamie@shareable.org>,
	qemu-devel@nongnu.org, Gleb Natapov <gleb@redhat.com>,
	kvm@vger.kernel.org
Subject: Re: [Qemu-devel] Re: qcow2 corruption observed, fixed by reverting old change
Date: Sat, 14 Feb 2009 23:56:58 -0800	[thread overview]
Message-ID: <aaccfcb60902142356o3249a906q4696ae608517a75e@mail.gmail.com> (raw)
In-Reply-To: <499745A1.3040707@redhat.com>

On Sat, Feb 14, 2009 at 2:28 PM, Dor Laor <dlaor@redhat.com> wrote:
>
> Both qcow2 and vmdk have the ability to keep 'external' snapshots.

I know but they don't implement one feature I cited: clones, or
"writable snapshots", which I would like implemented with support for
deduplication. Base images / backing files are too limited because
they have to be managed by the enduser and there is no deduplication
done between multiple images based on the same backing file.

> We might use vmdk format or VHD as a base for the future high performing,
> safe image format for qemu

Neither vmdk nor vhd satisfy my requirements: not always consistent on
disk, no possibility of detecting/correcting errors, susceptible to
fragmentation (affects vmdk, not sure about vhd), and possibly others.

Jamie: yes in an ideal world, the storage virtualization layer could
make use of the host's filesystem or block layer snapshotting/cloning
features, but in the real world too few OSes implement these.

-marc

WARNING: multiple messages have this Message-ID
From: Marc Bevand <m.bevand@gmail.com>
To: dlaor@redhat.com
Cc: qemu-devel@nongnu.org, Gleb Natapov <gleb@redhat.com>,
	kvm@vger.kernel.org
Subject: Re: [Qemu-devel] Re: qcow2 corruption observed, fixed by reverting old change
Date: Sat, 14 Feb 2009 23:56:58 -0800	[thread overview]
Message-ID: <aaccfcb60902142356o3249a906q4696ae608517a75e@mail.gmail.com> (raw)
In-Reply-To: <499745A1.3040707@redhat.com>

On Sat, Feb 14, 2009 at 2:28 PM, Dor Laor <dlaor@redhat.com> wrote:
>
> Both qcow2 and vmdk have the ability to keep 'external' snapshots.

I know but they don't implement one feature I cited: clones, or
"writable snapshots", which I would like implemented with support for
deduplication. Base images / backing files are too limited because
they have to be managed by the enduser and there is no deduplication
done between multiple images based on the same backing file.

> We might use vmdk format or VHD as a base for the future high performing,
> safe image format for qemu

Neither vmdk nor vhd satisfy my requirements: not always consistent on
disk, no possibility of detecting/correcting errors, susceptible to
fragmentation (affects vmdk, not sure about vhd), and possibly others.

Jamie: yes in an ideal world, the storage virtualization layer could
make use of the host's filesystem or block layer snapshotting/cloning
features, but in the real world too few OSes implement these.

-marc

  parent reply	other threads:[~2009-02-15  7:57 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-02-11  7:00 qcow2 corruption observed, fixed by reverting old change Jamie Lokier
2009-02-11  7:00 ` [Qemu-devel] " Jamie Lokier
2009-02-11  9:57 ` Kevin Wolf
2009-02-11 11:27   ` Jamie Lokier
2009-02-11 11:27     ` Jamie Lokier
2009-02-11 11:41   ` Jamie Lokier
2009-02-11 11:41     ` Jamie Lokier
2009-02-11 12:41     ` Kevin Wolf
2009-02-11 12:41       ` Kevin Wolf
2009-02-11 16:48       ` Jamie Lokier
2009-02-11 16:48         ` Jamie Lokier
2009-02-12 22:57         ` Consul
2009-02-12 22:57           ` [Qemu-devel] " Consul
2009-02-12 23:19           ` Consul
2009-02-12 23:19             ` [Qemu-devel] " Consul
2009-02-13  7:50             ` Marc Bevand
2009-02-16 12:44         ` [Qemu-devel] " Kevin Wolf
2009-02-17  0:43           ` Jamie Lokier
2009-02-17  0:43             ` Jamie Lokier
2009-03-06 22:37         ` Filip Navara
2009-03-06 22:37           ` Filip Navara
2009-02-12  5:45       ` Chris Wright
2009-02-12  5:45         ` Chris Wright
2009-02-12 11:08         ` Johannes Schindelin
2009-02-12 11:08           ` Johannes Schindelin
2009-02-13  6:41 ` Marc Bevand
2009-02-13 11:16   ` Kevin Wolf
2009-02-13 11:16     ` [Qemu-devel] " Kevin Wolf
2009-02-13 16:23     ` Jamie Lokier
2009-02-13 16:23       ` Jamie Lokier
2009-02-13 18:43       ` Chris Wright
2009-02-13 18:43         ` Chris Wright
2009-02-14  6:31       ` Marc Bevand
2009-02-14 22:28         ` Dor Laor
2009-02-14 22:28           ` Dor Laor
2009-02-15  2:27           ` Jamie Lokier
2009-02-15  7:56           ` Marc Bevand [this message]
2009-02-15  7:56             ` Marc Bevand
2009-02-15  2:37         ` Jamie Lokier
2009-02-15 10:57     ` Gleb Natapov
2009-02-15 10:57       ` [Qemu-devel] " Gleb Natapov
2009-02-15 11:46       ` Marc Bevand
2009-02-15 11:46         ` [Qemu-devel] " Marc Bevand
2009-02-15 11:54         ` Marc Bevand
2009-02-15 11:54           ` [Qemu-devel] " Marc Bevand

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