[Qemu-devel] Enhancing qemu-img convert format compatibility

[Qemu-devel] Enhancing qemu-img convert format compatibility

[Stefan Hajnoczi]

qemu-img is a pretty good Rosetta stone for image formats but it is
missing support some format versions.  In order to bring qemu-img
up-to-date with the latest disk image formats we will need to find
specific image files and/or software versions that produce image files
that qemu-img cannot understand today.

If you have image files that qemu-img is unable to manipulate, please
respond with details of the software and version used to produce the
image.  If possible please include a link to a small example image
file.

Stefan

Re: [Qemu-devel] Enhancing qemu-img convert format compatibility

[Richard W.M. Jones]

On Mon, Apr 18, 2011 at 11:18:42AM +0100, Stefan Hajnoczi wrote:
> qemu-img is a pretty good Rosetta stone for image formats but it is
> missing support some format versions.  In order to bring qemu-img
> up-to-date with the latest disk image formats we will need to find
> specific image files and/or software versions that produce image files
> that qemu-img cannot understand today.
> 
> If you have image files that qemu-img is unable to manipulate, please
> respond with details of the software and version used to produce the
> image.  If possible please include a link to a small example image
> file.

Stefan,

We found that using the vSphere 4.x "Export to OVF" option would
produce a VMDK file that qemu-img could not convert to raw.

For older qemu-img the file would be converted to something that was
not all zeroes, but nevertheless was certainly not a raw disk image.

For current qemu-img, we get an "Operation not permitted" error which
is at least better than silent corruption.

Full details are in this bug report:

https://bugzilla.redhat.com/show_bug.cgi?id=548723

Note the links at the top of that bug are broken.  The disk image
which failed is:

http://oirase.annexia.org/tmp/TestLinux-disk1.vmdk
  SHA1: 2c81bae89210b075acc51da9d025935470149d55
http://oirase.annexia.org/tmp/TestLinux.ovf
  SHA1: 30831689b8c6f1b1a1fcbb728769b5f71056a580

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
virt-df lists disk usage of guests without needing to install any
software inside the virtual machine.  Supports Linux and Windows.
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Re: [Qemu-devel] Enhancing qemu-img convert format compatibility

[Stefan Hajnoczi]

On Mon, Apr 18, 2011 at 12:03 PM, Richard W.M. Jones <rjones@redhat.com> wrote:
> On Mon, Apr 18, 2011 at 11:18:42AM +0100, Stefan Hajnoczi wrote:
>> qemu-img is a pretty good Rosetta stone for image formats but it is
>> missing support some format versions.  In order to bring qemu-img
>> up-to-date with the latest disk image formats we will need to find
>> specific image files and/or software versions that produce image files
>> that qemu-img cannot understand today.
>>
>> If you have image files that qemu-img is unable to manipulate, please
>> respond with details of the software and version used to produce the
>> image.  If possible please include a link to a small example image
>> file.
>
> Stefan,
>
> We found that using the vSphere 4.x "Export to OVF" option would
> produce a VMDK file that qemu-img could not convert to raw.

Excellent, thanks for sharing this.  I hope we can build a picture of
where there is missing support and address this in the "Improved Image
Format Compatiblity" project for Google Summer of Code:
http://wiki.qemu.org/Google_Summer_of_Code_2011#Improved_image_format_compatibility

Stefan