s qemu-img create -o preallocation=metadata -f qcow2 \
/var/lib/libvirt/images/demohostb 30G
# osinfo-query os | gr jessie
-s virt-install --os-variant debian8 --cpu host -n demohost --pxe -r 2048 --vcpus 1 --disk path=/var/lib/libvirt/images/demohost -w bridge=br0,mac=52:54:00:9c:ef:ad
+s virt-install --os-variant debian8 --cpu host -n demohost --pxe -r 2048 --vcpus 1 \
+ --disk path=/var/lib/libvirt/images/demohost \
+ --disk path=/var/lib/libvirt/images/demohostb -w bridge=br0,mac=52:54:00:9c:ef:ad