Comment 18 for bug 1776920

Bingo! Adding '-S 0' makes convert work. But it is not perfect as the end result is fully allocated image.

So with qcow2 like this:

image: mysql-example.qemu
file format: qcow2
virtual size: 10G (10737418240 bytes)
disk size: 50M
cluster_size: 65536
Format specific information:
    compat: 1.1
    lazy refcounts: false
    refcount bits: 16
    corrupt: false

and do this:

qemu-img convert mysql-example.qemu -S 0 -O vmdk mysql-example.vbox

I get 10G vmdk file:
10738794496 Jul 6 18:27 mysql-example.vbox