upgrading openbsd 4.6 to 4.7 and other xen considerations

i did this from a preexisting installation of openbsd 4.6. basically, all i did was downloaded the bsd.rd for openbsd 4.7 and copied it where the existing one was. i restarted the machine and at the boot> prompt i entered 
boot> boot hd0a:bsd.rd
what remained was exactly like booting from a 4.7 install cd. i selected upgrade and now i have openbsd 4.7 up and running. yay!