With compression parameters, it will be slow qemu-img convert -O qcow2 -c vm_pbc.qcow2 vm_pbc_shrink.qcow2 Operate on the host qemu-img convert -O qcow2 vm_pbc.qcow2 vm_pbc_shrink.qcow2
Download SDelete Save to C:\windows\system32\.
Use SDelete (recommended) or Eraser to fill the free space with 0.
Qemu-img create -f qcow2 centos7-guest.qcow2 10G QEMU img command Create mirror qemu-img create # Create an image with a device space of 10G