Hi,
As I am trying to migrate virtual machine from one physical host to different physical host system but getting following error " unable to migrate guest: internal error: unable to execute QEMU command ‘migrate’: Block format ‘qcow’ used by device ‘drive-virtio-disk0’ does not support feature ‘live migration’ … screenshot can be seen from below link.
I am able to see this virtual machine on other physical system but unable to perform migration due to above error!!
Please let me know what block format will be supported for migration or what else can be done !! 
Thanks,