First, I'd say that if you are converting an image over to use on Hyper-V, you would probably be better served using the VHDX format (completely different from VHD) - it is the newer format (and completely different from VHD), and is supported by QEMU as well. It is better defined and more consistent (at least so far) in its specification.
That said, I think for the specific VHD problem we could look at the Creator field in the image. My only reservations on that are: 1.) I haven't looked at the Creator field comprehensively across all revisions of Hyper-V and Virtual PC. But in my small sample size, it seems feasible. 2.) It most likely won't be 100%, because of edge cases (e.g. I don't know what happens when Hyper-V opens a Virtual-PC produced VHD file, and under what circumstances it may or may not alter the Creator field) But the above two reservations can be overcome with the appropriate options that can be passed to the VHD format, to override the auto- detection method. I have access to both Virtual PC and Hyper-V, so I can put together a small patch series tomorrow to try that out. -- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1490611 Title: Using qemu >=2.2.1 to convert raw->VHD (fixed) adds extra padding to the result file, which Microsoft Azure rejects as invalid Status in QEMU: Fix Released Bug description: Starting with a raw disk image, using "qemu-img convert" to convert from raw to VHD results in the output VHD file's virtual size being aligned to the nearest 516096 bytes (16 heads x 63 sectors per head x 512 bytes per sector), instead of preserving the input file's size as the output VHD's virtual disk size. Microsoft Azure requires that disk images (VHDs) submitted for upload have virtual sizes aligned to a megabyte boundary. (Ex. 4096MB, 4097MB, 4098MB, etc. are OK, 4096.5MB is rejected with an error.) This is reflected in Microsoft's documentation: https://azure.microsoft.com /en-us/documentation/articles/virtual-machines-linux-create-upload- vhd-generic/ This is reproducible with the following set of commands (including the Azure command line tools from https://github.com/Azure/azure-xplat- cli). For the following example, I used qemu version 2.2.1: $ dd if=/dev/zero of=source-disk.img bs=1M count=4096 $ stat source-disk.img File: ‘source-disk.img’ Size: 4294967296 Blocks: 798656 IO Block: 4096 regular file Device: fc01h/64513d Inode: 13247963 Links: 1 Access: (0644/-rw-r--r--) Uid: ( 1000/ smkent) Gid: ( 1000/ smkent) Access: 2015-08-18 09:48:02.613988480 -0700 Modify: 2015-08-18 09:48:02.825985646 -0700 Change: 2015-08-18 09:48:02.825985646 -0700 Birth: - $ qemu-img convert -f raw -o subformat=fixed -O vpc source-disk.img dest-disk.vhd $ stat dest-disk.vhd File: ‘dest-disk.vhd’ Size: 4296499712 Blocks: 535216 IO Block: 4096 regular file Device: fc01h/64513d Inode: 13247964 Links: 1 Access: (0644/-rw-r--r--) Uid: ( 1000/ smkent) Gid: ( 1000/ smkent) Access: 2015-08-18 09:50:22.252077624 -0700 Modify: 2015-08-18 09:49:24.424868868 -0700 Change: 2015-08-18 09:49:24.424868868 -0700 Birth: - $ azure vm image create testimage1 dest-disk.vhd -o linux -l "West US" info: Executing command vm image create + Retrieving storage accounts info: VHD size : 4097 MB info: Uploading 4195800.5 KB Requested:100.0% Completed:100.0% Running: 0 Time: 1m 0s Speed: 6744 KB/s info: https://[redacted].blob.core.windows.net/vm-images/dest-disk.vhd was uploaded successfully error: The VHD https://[redacted].blob.core.windows.net/vm-images/dest-disk.vhd has an unsupported virtual size of 4296499200 bytes. The size must be a whole number (in MBs). info: Error information has been recorded to /home/smkent/.azure/azure.err error: vm image create command failed I also ran the above commands using qemu 2.4.0, which resulted in the same error as the conversion behavior is the same. However, qemu 2.1.1 and earlier (including qemu 2.0.0 installed by Ubuntu 14.04) does not pad the virtual disk size during conversion. Using qemu-img convert from qemu versions <=2.1.1 results in a VHD that is exactly the size of the raw input file plus 512 bytes (for the VHD footer). Those qemu versions do not attempt to realign the disk. As a result, Azure accepts VHD files created using those versions of qemu-img convert for upload. Is there a reason why newer qemu realigns the converted VHD file? It would be useful if an option were added to disable this feature, as current versions of qemu cannot be used to create VHD files for Azure using Microsoft's official instructions. To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1490611/+subscriptions
