advice

All, We're migrating from our existing FreeRADIUS/MySQL setup to a new one. The new config is up and running in a different colo site and I'm looking for advice as to how I can overlap the two RADIUS servers temporarily without having two DBs running. Would it be best to have the old RADIUS server write to the new MySQL DB, or rather have the old RADIUS server proxy *all* requests to the new RADIUS server, or any other fabulous ideas you all may have? I'm a bit of a newbie, only been working on this for a bit now... so any/all information would be greatly appreciated! Thanks! -michelle.