compress qcow2 qemu-kvm

qemu-img convert  source_not_compressed_qcow2.img -O qcow2 -c  target_compressed_qcow2.img

Пример

qemu-img convert /home/vm/nfsshare-vmmanager.qcow2 -O qcow2 -c /home/vm/nfsshare-vmmanager_compress.qcow2