Even with thin provisioning, QCOW2 images can "balloon" over time as you install and delete files. To shrink your image back down to its true size, use the SDelete tool from Microsoft Sysinternals Google Groups Inside your Windows 7 VM, run: sdelete -z c: to zero out free space. Shut down the VM. On your host, convert the image to a new, compressed file:
That’s the piece. If you meant something more technical — like performance tuning for a Windows 7 QEMU image under load — I can write that too. Just say the word. windows 7 qcow2 top