I have a Windows 2008 SP2 server running as a primary domain controller with active directory, file shares, DHCP, DNS, and MS SQL 2008. I plan on upgrading to 2008 R2 (with the same SKU) to take advantage of some of the new features included in this release.
If I just pop in the CD in and run through the upgrade process, will active directory's functional level remain at the 2008 level, or will it be upgraded to 2008 R2?
I have a mixed environment of XP, Vista, and Windows 7 workstations. Are there any other considerations I should be aware of or prepare for?