I am looking for document that explains the best way of adding a backup domain controller to our existing network. I presently have a Windows 2003 VM server that is running AD, DNS, and DHCP. I want to create another server that will take over if the primary goes down. So far I have created a new Windows 2003 VM server and just added it to the domain. My reason for doing this is so that if my main domain controller goes down I have another one to fall back to. Is this a good idea to do?