Hi all,

i want to migrate my server windows 2003 R2 to Windows Server 2008 R2. currently, i have 2 servers each as DC and ADC also 1 server for migration purpose. my goal is 2 servers DC with Windows Server 2008 R2 and leave 1 server with 2003 R2.

please tell me what plan i need to do to migrate them without no downtime ?

thank you.

I'd build a new 2008 R2 SP1 on the spare box, patch it fully, then you can follow along here to join, promo and migrate roles over to new server.

http://blogs.msmvps.com/mweber/2010/02/10/upgrading-an-active-directory-domain-from-windows-server-2003-to-windows-server-2008-or-windows-server-2008-r2/

You may want to take a look below two links.

http://kpytko.pl/active-directory-domain-services/adding-first-windows-server-2008-r2-domain-controller-within-windows-2003-network/

http://blog.zwiegnet.com/windows-server/migrate-server-2003-to-2008r2-active-directory-and-fsmo-roles/