QCOW format not working?

Question

ubuntu

When installing a virtual machine, if you create a QCOW 2 disk , then everything is fine. But if you set the QCOW format with dynamic allocation of disk space, for example, from 8 to 20 for Ubuntu 16.04.1, it freezes when copying / unpacking. Why can this happen? RAW is the same, it hangs during installation. The disk on the SSD host, there is relatively little space (120Gb), I would like to create a virtual machine with a dynamic format.

Answer 1

I don't know why, but if everything is done through the virtual manager, or through virt-install --disk path=/path/12.04.img,size=10,format=qcow2, then the entire disk is created. And if so qemu-img create -o -f qcow2 qcow2.img 20G - then what you need ..