I have 3 DCs (Windows 2003 enterprise SP1), one of them is currently running of diskspace. Since this one is a 5 years old server. I want to buy a new server and migrate this existing one the new one. The existing one is currently a DC which is also holding a secondary WIN. What is the best way to handle this migration which won't create any downtime, and also how to find out whether this existing DC holding another other roles in addition to DC and secondary WIN.