KVM
Сжать qcow2
qemu-img convert -O qcow2 /path_to_you_image/you_name_image.qcow2 /path_to_you_image/you_name_image.qcow2
Конвертировать из qcow2 в raw
qemu-img convert -f qcow2 -O raw /path_to_you_image/you_name_image.qcow2 /path_to_you_image/you_name_image.raw