Windows GuestThe idea here is simple, there are few things you have to do:
- Delete all unnecessary files, empty recycle bin
- Defragment drive (you might need to do this several times, until you see it "compacted" well)
- Use sdelete to zero free disk space. Please note that this operation will cause that all drive free space will be filled by zero, so the virtual machine image will grow to the maximum size.
sdelete -c c:
dd if=/dev/zero of=./zero bs=1M sync rm -f ./zeroNote, the bs parameter is important, since it greatly reduce time necessary to complete this task.
HostConvert image to the same format that is currently is (e.g. qcow2 => qcow2)... during this procedure it will release unused space.
qemu-img convert -O qcow2 w2k3.qcow2 \ w2k3-shrinked.qcow2The process is time consuming and each phase greatly depends on physical disk IO performance and available free space.