Server 2008 in a mixed environment

[JJonas]

Im looking for some advice.

We have five servers running a mixture of Server 2003 with SP2 and Server 2003 R2.

We want to upgrade one of these servers to Server 2008 with the eventual plan of upgrading all of them over time.

We are planning to upgrade our WSUS server to start with as it only deals with updates it wont be too much of a disaster if the update kills it.

Is it safe just to upgrade one server at a time of do we need to do them all at the same time. Is doing it this way going to cause problems for active directory. Is there a recommended way of going about an upgrade?

[cookie_monster]

Well MS don't recommend upgrading servers you're better going with a clean install. Member servers can by upgraded or added to the domain at any time without any impact but DC's will require more planning.
With DC's you're better off having either a swing server or if you have a few DC's demoting one then reinstalling with 2008 and making it a DC. You must prep the domain first though have a search on the forum there's loads of threads on this. If you happen to have a nice reliable DC with quality supported hardware with 2008 drivers you could consider an upgrade on that one DC and then demote the others and reinstall with 2008 and re add to the domain, MS recommend not to re use the same name for a new DC.

[AIT]

Im looking for some advice.

We have five servers running a mixture of Server 2003 with SP2 and Server 2003 R2.

We want to upgrade one of these servers to Server 2008 with the eventual plan of upgrading all of them over time.

We are planning to upgrade our WSUS server to start with as it only deals with updates it wont be too much of a disaster if the update kills it.

Is it safe just to upgrade one server at a time of do we need to do them all at the same time. Is doing it this way going to cause problems for active directory. Is there a recommended way of going about an upgrade?

depending on what roles they are doing its safe to do one at a time. Your WSUS one would be a good one to start.

also it is better to do a fresh install.

I would 100% no do an upgrade on your dc's though.