Upgrading from Windows 2003 to Windows 2008

We have no Windows Server 2008 systems in production yet, but I've upgraded about 6 test servers (1 32-bit, 5 64-bit) and the process has been nearly flawless. However, most have been VMware-hosted VMs, the driver issues aren't a big deal. The only thing I've had to do is uninstall/reinstall McAfee VirusScan 8.5 after the upgrade.

I think Microsoft has had a lot of time to improve the upgrade process since the NT4->Windows 2000 days. I did a lot more Windows 2000->2003 upgrades than NT4->W2K, that's for sure. I will only be recommending upgrades (when absolutely required) of W2K3 x64 -> W2K8 x64. I don't want to use W2K8 32-bit in production as a best practice.

My opinion only but if its a production server I would never consider an upgrade. Pull the drives, slap in some new ones, do your Windows 2008 install and if you run into problems plug the old drives back in.

I don't think the server path for upgrades is any better than the workstation path. It's the same core product after all. What you might have, however, well hopefully have, is less "odd crap" on the system that might trip an upgrade up.

You need to grab a practice image, possibly into a virtual machine, and test how the upgrade goes for you, see how your apps behave on an upgraded system and decide if the time taken to upgrade server, upgrade your apps, and debug is less than the time taken to build a new system and migrate across.

Oh yeah, unless you are virtualising the production machine, check the hardware is compatible with Win 2008. That would be a real nasty one.

As for a rollback plan as chopper3 suggests, thats really important too. Make sure you don't start the upgrade process until you're sure you can restore a backup of the Windows 2003 server you're upgrading.

If minimal downtime is your prime concern then copying the system's drives, performing an upgrade, testing the upgrade, then rolling back if something has gone wrong, it not the way to go. Not for the reason that there might be problems with the upgrade, but because there are other plans that will most likely result in far less downtime from your users' point of view.

For minimum downtime I would suggest:

1. install the OS a second machine
2. copy the application(s), data, configuration and other resources across
3. test as much as you can
4. turn off the services on the old server
5. do a final sync onto the new server (so it has any updates that happened to the old server during the time you were building and testing)
6. reconfigure the relevant things (the server and/or network settings elsewhere) so that the new server appears where the old one was
7. leave the old server running for a short while (or just keep its drives handy) in case you discovered later that you forgot to transfer something over

This way the only downtime you have is the time it takes to perform that final sync before switching over (steps 5 and 6) - this might be a while if the final sync includes copying some large files (such as one or more big databases) over, but this will be less time than a taking a complete backup image and upgrading will take and has the advantage of no downtime if it fails (as you just drop the new setup without ever turning the old one off).

Of course this plan means having a second server in the same facility to build on which will not be free, so if you are paying a fair chunk for your server/hosting or are otherwise on a tight budget this might be a prohibitive factor...

We've upgraded non-critical systems on 32-bit without any real issues. I wouldn't consider a Windows upgrade for a mission-critical application, however, primarily due to the downtime it would create. When upgrading a critical app, we usually purchase a new server for the newer OS and then migrate the application from one to the other. The older server can then be resold or re-purposed elsewhere.

My main reason for not doing upgrades is cleanliness and disk space.

The last point is that I had lots of Dell servers which were sat on 12Gb System partitions, as service packs and patches have been applied over the years the amount of disk space has just diminished with no nice solution available.

I wouldn't really want to take all of this 'baggage' on to a new OS with me.

I tried the upgrade path in Virtual PC, i can admit that it better to migrate instead to upgrade. The two os are completely different

I'd just ask yourself why you'd want to upgrade and what's your rollback plan?

Its not worth the risk for a production machine.

You'll sleep better knowing you have a default install that 99% of the world uses and manufacturers ship with.

Go with the widest tested setup rather than the least.