Re: [Qemu-devel] [PATCH] vmdk: improve streamOptimized vmdk support

[Stefan Hajnoczi]

On Tue, Jul 29, 2014 at 2:46 PM, Milos Vyletel <address@hidden> wrote:
> On Tue, Jul 29, 2014 at 9:37 AM, Stefan Hajnoczi <address@hidden> wrote:
>> On Mon, Jul 07, 2014 at 10:54:27AM -0400, Milos Vyletel wrote:
>>> VMDK's streamOptimized format is different that regular sparse format.
>>> L1(GD) and L2(GT) tables are not predefined but rather generated and
>>> written during image creation mainly because there is no way to tell
>>> how much space data will occupy once they are compressed. Also the
>>> location of header, L1 and L2 tables differs.
>>>
>>> - L2 tables (grain tables) are written after all grains they point to
>>> - L1 tables are written after all grains and L2 tables
>>> - footer at the end is used instead of header in first sector
>>>
>>> This patch improves streamOptimized support and adds possibility to
>>> create true streamOptimized images using qemu-img. Some of the changes
>>> are from VMDK specs, some of them from hexdump-ing images from VMWare
>>> and VirtualBox.
>>>
>>> I have compared these images to the ones generated by VMWare and vbox
>>> and they are identical with the exception of DescriptorFile that has
>>> some differences but none that would change behavior(CID and some
>>> additional DDB entries differ) and streamOptimized image generated from
>>> raw image was succesfully imported (as OVA) into VMWare ESXi and Oracle
>>> OVM.
>>>
>>> Signed-off-by: Milos Vyletel <address@hidden>
>>> ---
>>>  block/vmdk.c |  363 
>>> +++++++++++++++++++++++++++++++++++++++++++++-------------
>>>  1 files changed, 281 insertions(+), 82 deletions(-)
>>
>> What does this patch do beyond what QEMU already supports today?
>>
>> Is there a particular application that rejected QEMU's streamOptimized
>> images?  Is this a bug fix?
>>
>> Please use scripts/checkpatch.pl to check coding style.
>>
>> Fam: Please review
>>
>
> Images created/converted using QEMU were rejected by VMWare ESXi,
> vCloud, VirtualBox and Oracle OVM. I did not try anything else.
>
> Generally speaking streamOptimized format is not followed by QEMU.
> Instead regular VMDK format + encryption is used. We can say this is
> bug fix since streamOptimzed format is already included but does not
> work well.
>
> I'll check the style and fix the code. I'll postpone resubmit until
> further review is done since I'm sure there will be things that will
> need to be fixed.

What was the command-line you used?

qemu-img convert -f qcow2 -O vmdk -o subformat=streamOptimized
input.qcow2 output.vmdk

Stefan