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Description of problem: I created one 1GB VHD(Fixed size) format image via, but qemu-img fail to recognize the Hyper-V Virtual Hard Disk (VHD) format image. BTW, QEMU can used it as read-only device to boot up and can detect it in guest correctly. I will attach the image for your debugging. Version-Release number of selected component (if applicable): host info: # uname -r && rpm -q qemu-kvm-rhev 2.6.32-493.el6.x86_64 qemu-kvm-rhev-0.12.1.2-2.431.el6.x86_64 How reproducible: 100% Steps to Reproduce: 1.create a VHD(Fixed size and Dynamically expanding) format image via Hyper-v(Hyper-V Manager Verfison: 6.3.9600.16384) in Window Server 2012 R2. e.g.1.Choose Disk Format(VHD)----Choose Disk Type(Fixed size)----1GB sluo1-fixed-size.vhd e.g.2.Choose Disk Format(VHD)----Choose Disk Type(Dynamically expanding)----1GB sluo2-dynamically-expanding.vhd 2.Copy out the VHD images to local host and use qemu-img to recognize them or convert to qcow2 image. # qemu-img info sluo1-fixed-size.vhd # qemu-img info sluo2-dynamically-expanding.vhd 3.Launch a KVM guest with the VHD image as read-only device. e.g.:...-drive file=/home/sluo1-fixed-size.vhd,if=none,format=vpc,id=drive-data-disk,cache=none,werror=stop,rerror=stop,readonly=on -device virtio-blk-pci,bus=pci.0,addr=0x7,drive=drive-data-disk,id=data-disk Actual results: after step 2, # qemu-img info sluo1-fixed-size.vhd image: sluo1-fixed-size.vhd file format: raw <----------------- should be vpc virtual size: 1.0G (1073742336 bytes) disk size: 1.0G # qemu-img info sluo2-dynamically-expanding.vhd image: sluo2-dynamically-expanding.vhd file format: vpc virtual size: 1.0G (1073479680 bytes) disk size: 8.0K cluster_size: 2097152 # qemu-img convert -p -f vpc -O qcow2 sluo1-fixed-size.vhd test1.qcow2 (100.00/100%) # qemu-img convert -p -f vpc -O qcow2 sluo2-dynamically-expanding.vhd test2.qcow2 (100.00/100%) after step 3, boot up KVM guest successfully and the VHD disk can be detected in guest correctly. Expected results: qemu-img can recognize the Hyper-V Virtual Hard Disk (VHD) format image correctly. Additional info:
Hi Sibiao, Thanks for the sample issue. For fixed-sized VPC (VHD) images, qemu currently cannot autodetect the type during a probe. This is because for a format-probe, QEMU sends a data chunk from the beginning of the file to each image format driver, to detect header signatures / magic. However, fixed sized VPC/VHD images only have a footer at the end of a file, and no header at the beginning. This means that the image will most likely just be detected as 'raw'. This could be changed upstream, as a feature enhancement.
(In reply to Jeff Cody from comment #3) > Hi Sibiao, > > Thanks for the sample issue. For fixed-sized VPC (VHD) images, qemu > currently cannot autodetect the type during a probe. This is because for a > format-probe, QEMU sends a data chunk from the beginning of the file to each > image format driver, to detect header signatures / magic. However, fixed > sized VPC/VHD images only have a footer at the end of a file, and no header > at the beginning. This means that the image will most likely just be > detected as 'raw'. > > This could be changed upstream, as a feature enhancement. Yes, thanks for your detail explains. BTW, qemu-img can recognize for the VHDX(Fixed size/Dynamically expanding) as vhdx correctly. Choose Disk Format+----VHD----Choose Disk Type+----Fixed size | | | +----Dynamically expanding | | | +----Differencing | +----VHDX---Choose Disk Type+----Fixed size | +----Dynamically expanding | +----Differencing # qemu-img info sluo3-fixed-size.vhdx image: sluo3-fixed-size.vhdx file format: vhdx virtual size: 1.0G (1073741824 bytes) disk size: 1.0G cluster_size: 33554432 # qemu-img info sluo4-dynamically-expanding.vhdx image: sluo4-dynamically-expanding.vhdx file format: vhdx virtual size: 1.0G (1073741824 bytes) disk size: 4.0M cluster_size: 33554432 Best Regards, sluo