How to shrink OpenStack qcow2 image using qemu-img
If you transfer qcow2 images very frequently across OpenStack Clouds or between KVM and Openstack environments, they can quickly grow larger. Luckily qcow2 image size can be decreased to reasonable values using qemu-img tool. During image conversion the empty sectors are detected and suppressed from the destination image. Below we present how to shrink Openstack/KVM qcow2 image.