The Exchange Team have produced a post regarding the installation of Exchange on Windows Server 2008 http://msexchangeteam.com/archive/2007/08/16/446709.aspx. There a number of implications that need to be thought through and I would advise all Exchange administrators to read the post at least twice!
- it is NOT possible to do a rolling upgrade of an Exchange cluster on Windows Server 2003 to Windows Server 2008
- Windows Server 2008 DCs should NOT be installed in sites with Exchange 2000 serves
- Exchange does NOT use RODCs
The restrictions could have some serious implications for the order in which upgrades are performed.