> It was never in qemu upstream. > > qemu dev prefer to not maintain to much disk format . (FVD seem to be great > on the paper) I just wrote a mail to the developer - maybe I will get a reply. > They prefer to take idea from FVD and push them in the (futur) qcow2 v3 Yes, but qcow3 is also non-existent? Or do they simply improve qcow2 now?