rbd to qcow2 file format

# rbd export vm5891121 vm5891121.img -p volumes
# qemu-img convert -f raw -O qcow2 vm5891121.img vm5891121.qcow2

raw to qcow convert конвертирование

qemu-img convert -f raw -O qcow2 vm2505705 vm2505705.qcow