Comment 3 for bug 1881231

primary vm command:
./qemu-system-x86_64 -L /usr/share/qemu-kvm/ -enable-kvm -cpu qemu64,+kvmclock -m 2048 -smp 2 -qmp stdio -vnc :0 -device piix3-usb-uhci -device usb-tablet -name primary -netdev tap,id=hn0,vhost=off,br=br_bond1,helper=/usr/libexec/qemu-bridge-helper -device rtl8139,id=e0,netdev=hn0,romfile="" -chardev socket,id=mirror0,host=169.254.66.11,port=9003,server,nowait -chardev socket,id=compare1,host=169.254.66.11,port=9004,server,wait -chardev socket,id=compare0,host=169.254.66.11,port=9001,server,nowait -chardev socket,id=compare0-0,host=169.254.66.11,port=9001 -chardev socket,id=compare_out,host=169.254.66.11,port=9005,server,nowait -chardev socket,id=compare_out0,host=169.254.66.11,port=9005 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 -object iothread,id=iothread1 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,iothread=iothread1 -drive if=ide,id=colo-disk0,driver=quorum,read-pattern=fifo,vote-threshold=1,children.0.file.filename=/root/Centos7.4.qcow2,children.0.driver=qcow2 -S

secondary vm:
./qemu-system-x86_64 -L /usr/share/qemu-kvm/ -enable-kvm -cpu qemu64,+kvmclock -m 2048 -smp 2 -qmp stdio -vnc :1 -device piix3-usb-uhci -device usb-tablet -name secondary -netdev tap,id=hn0,vhost=off,br=br_bond1,helper=/usr/libexec/qemu-bridge-helper -device rtl8139,id=e0,netdev=hn0,romfile="" -chardev socket,id=red0,host=169.254.66.11,port=9003,reconnect=1 -chardev socket,id=red1,host=169.254.66.11,port=9004,reconnect=1 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 -object filter-rewriter,id=rew0,netdev=hn0,queue=all -drive if=none,id=parent0,file.filename=/root/Centos7.4.qcow2,driver=qcow2 -drive if=none,id=childs0,driver=replication,mode=secondary,file.driver=qcow2,top-id=childs0,file.file.filename=/root/active.qcow2,file.backing.driver=qcow2,file.backing.file.filename=/root/hidden.qcow2,file.backing.backing=parent0 -drive if=none,id=colo-disk0,driver=quorum,read-pattern=fifo,vote-threshold=1,children.0=childs0 -incoming tcp:0:9998