Re: [Qemu-devel] QCOW(2) image corruption under QEMU 0.9.0 reproducible

From: Julian Seward <jseward@acm.org>
To: qemu-devel@nongnu.org
Cc: herbie hancock <hhancock@web.de>
Subject: Re: [Qemu-devel] QCOW(2) image corruption under QEMU 0.9.0 reproducible
Date: Thu, 15 Mar 2007 09:59:46 +0000	[thread overview]
Message-ID: <200703150959.46223.jseward@acm.org> (raw)
In-Reply-To: <1730805162@web.de>

Something similar happened to me.  At first I thought it was a hardware
(host) problem and so do not have good details - this is from memory.

- 0.9.0, binary build from qemu.org
- i386 openSUSE 10.2 host
- RedHat 8 guest
- .qcow2 image, max size 8GB
- using the Accelerator but not -kernel-kqemu

- first sign of trouble was the ext3 driver in RedHat8 complaining of
  something about disk geometry (something % 4 was not zero when it
  should have been)

- this is when the disk image was about 3G in size

- shortly thereafter the disk image was so corrupted that e2fsck
  could not fix it

- IIRC, ls -l on the corrupted image showed some implausibly huge size
  (> 100GB ?) leading me to believe the file had some huge block of
  zeroes in the middle

J

On Wednesday 14 March 2007 23:20, herbie hancock wrote:
> Hello, i had also a reproducible disk crash:
> info of the last good image, size is about 3,5GB
>
> image: debian4_0.dsk file format: qcow2 virtual size: 16G (16777216000
> bytes) disk size: 3.3G cluster_size: 4096
>
> as soon as the image increase to a size of about 7,9 GB the emulator locks
> up, and after a restart the the image is not readable any more. the start
> of the image is filled with zeros, the signature of the file  at the start
> (QFI ....)  is overwritten.
>
> I tried it two times, started with a intact image with the size above and
> in both times the image was corrupted.
>
> Host: WIN2K
> Guest: Debian 4.0 Etch.
> qemu: 0.90 (build date 2007-02-19, the version that comes with
> http://www.davereyn.co.uk/qem/setupqemuk40.exe)
>
> I tested the image above with virtualbox (installed backup of the qemu disk
> with acronis trueimage and bart pe boot cd) , started with the above image,
> and the problems are gone, image is now filled with more than 9GB, no
> problem so far.
>
> I never experienced such a bad problem with qemu before, maybe it is a
> problem with qcow2 format ?
>
> Bye
> HR
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