Re: [Qemu-devel] [PATCH 0/7] block-vpc: Improve support for VHD images

[Kevin Wolf]

Jamie Lokier schrieb:
> Kevin Wolf wrote:
>> This patch series improves the support for Virtual PC images. Until
>> now, support for this image format is read-only and broken for large
>> images. With these patches applied, you can create and write to VHD
>> Dynamic Disks and some bugs in the read support are fixed. They have
>> been tested with qemu-img convert from and to raw images and a
>> successful openSUSE installation on a fresh VHD image.
> 
> Ooh, I look forward to trying these patches. :-)
> 
> I have some VHD image of Windows which always resulted in lots of
> scandisk errors when Windows booted from it (using -snapshot), and the
> same when converted to a QCOW2 file by qemu-img.

I think there is only one integrity patch in the series which fixes
images > 4 GB. Is this the case with your image?

> (By the way, VPC took *ridiculously* long - about 8 hours for an 80GB
> sparse image.  VirtualPC appears to use unbuffered writes (equivalent
> to O_DIRECT) at least when over SMB, but they are small writes and not
> overlapped, so it trickles along very slowly).

Well, my implementation probably isn't that fast as well. It's the
simplest one I could think of and it's mostly to have at least something
to convert images. I don't think I would run a VM on it except for testing.

> So I look forward to trying these patches on that image, which I don't
> use know but kept for this very purpose, and seeing if it's fixed the
> errors.

Thanks for testing and please report back. I hope it works fine now.

Kevin