Hi, 168468fe19c8 ("qemu-img: Add --target-is-zero to convert") has added a nice functionality for cloud scenarios:
* Create a virtual disk * Convert a sparse image (qcow2, vmdk) to the virtual disk using --target-is-zero * Use the virtual disk This saves many unnecessary writes - a qcow2 with 1MB of allocated data but with 100GB virtual size will be converted efficiently. However, does this pose a problem if the virtual disk is not zero initialized? Theoretically - if all unallocated blocks contain garbage - this shouldn't matter, however what about allocated blocks of zero? Will convert skip copying allocated zero blocks in the source image to the target since it assumes that the target is zeroed out first thing? Sam