Migration Vs upgrading

[Fartout]

I 'm looking for documents about the disadvantages to performing an in-place upgrade, or Help.

 

[Seaspray0]

Here's one... Windows 2003 Help and Support:

Getting Started>Installing and Upgrading the Operating System>Concepts>Upgrading or Installing>Upgrades compared to New Installations.




A+/MCP/MCSE/MCDBA

 

[MTVW]

In place is fairly straight forward and leaves everything in tact. Side by side takes a little more effort from an administrative standpoint.

It all depends what your current structure is which is the best plan

 

[MTVW]

A lot of people say there is no real fall back plan and that an inplace is risky....I disagree. You designate a rollback server...which can very well be your current PDC.
This server will be unplugged from the network during the actual upgrade. If the upgrade fails....you disconnect the failed 2003 DC (and any others) then plug the roll back in and promote it.

One thing to keep in mind is DC overload. When Windows 2000 and XP clients first boot up they look to use Kerberos authentication which is more secure and is only available in an AD domain. NT4 uses NTLM. If clients see a DC supports Kerberos they will all use this DC. To prevent this, prior to upgrading the PDC you need to put the NT4Emulator DWord Key in the registry. HKLM\System\CCS\Services\Netlogon\Parameters

This makes client machines think it is still an NT domain and use NTLM until you are comfortable with everything AD.
Also if you want to add new 2003 DC's each DC will need this key along with the NeutralizeNT4Emulator Dword Key. Without this AD will not install.

There are more steps but these are pretty important.