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First of all I am a novice and I have a huge task on my hands. This is what's going on:

I am running a Windows 2008 server. This Server runs AD, DHCP, DNS and shares some files.

Now I need to move the everything to a new server with Windows 2008 R2.

What is the best approach to do this, with minimal to no downtime for the users.

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up vote 5 down vote accepted

First of all, I don't want to sound rude but this is absolutely basic windows system administration stuff. The details are covered in countless books, on-line blog articles, the Microsoft website, etc. Most of the time this sort of thing will go really smoothly with no problems, but when it goes wrong it can go very wrong very quickly. Nobody ever said "boy we had just too many backups and tests there, what were we thinking" after doing something like this...

There's lots of help out there (and here of course!) but you will need to do either do some of that research or hire a consultant for a day or two's work to do this - no one can give you an absolutely foolproof "cookbook" set of instructions to follow. But I'll give you an outline that breaks it down into smaller manageable chunks...

The most painless way of doing this would be to configure the new server as a member of the domain the old one is hosting, then add the domain controller, DNS and DHCP roles and promote the new server to be a second domain controller in the original domain.

That's all your accounts and so-on transferred.

The configure DNS to get its info from the first server's DNS (hopefully stored in AD anyway). That's DNS configured.

DHCP - I'd just set this up as a new DHCP server when you're ready rather than bothering to do anything else. You'll want to update DNS info and the like in DHCP settings to refer to the new server, not the old.

At this point you've got the server online and done a fair amount of setup with no downtime to users. Not bad eh?

Not used it myself but microsoft have a tool for migrating file shares to a new file server. You'll want to then move all the users over to using the new server for their files at this point, which might involve either some downtime or some running around after hours while everyone else is off home(you don't want some users accessing files on the new server and others accessing them on the old one, do you?).

At this point, you can leave the old and new server running side by side for as long as you like, so test test test. Disable DHCP on the old server and make sure it works on the new one (so you can just re-enable it on the old server if you have problems). When you are ready, shut down the old server and test test test some more to make sure the network behaves as expected.

At this point you need to decommission the old server - uninstall AD properly, using the guides that are out and about - this is the area that possibly carries some risk if you mess it up, so if you only take my advice about considering getting help and/or researching and understanding stuff before doing it for one little part of what you're doing then make it this part.

Actually at this point, rather than decommission the old server, I'd consider just tidying up the file server role and using it as an additional domain controller. This can improve your network's reliability and make it much easier to get going again if the new server should happen to break down.

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+1 to keeping the old machine. No one should have a single DC domain, unless it's for a test environment that you wouldn't mind rebuilding. – mfinni Jan 5 '11 at 21:01

Build the new server. Add it to the domain. Configure DNS on it. Migrate all the FSMO roles to it.

One night, turn off DHCP on the old server and authorize it on the new one. Configure it the same way as the old one, but with itself as the DNS server for clients. Unless you have a complex DHCP config, just do this manually.

That covers everything except your fileshares. You can migrate those manually by copying the files, recreating the share(s), and pointing the clients to the new server. Or you can use the file migration toolkit from MS. It depends on how many users, how many shares, how much data.

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Get someone who knows what they're doing. It's a Really Bad Idea™ to be trying this alone.

If the previous server was 64-bit, then you can do a straight upgrade. Take at least two backups (verify them) first.

If it was 32-bit, you have to transition the roles over, and it's somewhat involved. Definitely something I would recommend finding a professional for.

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Actually, this is pretty bog-standard for a junior admin, don't you think? – mfinni Jan 5 '11 at 20:58
I don't know if its common is it to migrate these things over? I think it's a topic that in a larger network wouldn't necessarily be a big deal since usually you have redundant AD servers that would take care of most of the OP's questions; except for DHCP and file sharing, maybe. Is there already a redundant configuration of AD servers or is this the only one?...that could be the bigger problem. – Bart Silverstrim Jan 5 '11 at 21:07
@Mfinni, if by "junior admin" you mean that there's an experience admin around who has thought through the assignment and determined there to be minimal risk to the network, then yes, completely agree. If you mean the guy who used to do bookkeeping and knows a little about computers so the boss decided he could do this "upgrade" (cause consultants are too expensive), then no, sounds like impending doom. These things are pretty straight forward as others have noted, but it can all go sideways very badly very quickly too... – Chris S Jan 5 '11 at 22:03

All of the services you listed can be configured in a multiple server, redundant setup (except file sharing).

DHCP-failover, backup domain controller, slave DNS. You should be able to setup the two servers in tandem, then bring down the old one and promote the new one to primary on all three.

File sharing is the only thing that takes longer; you'll have to copy over all the files, make the old server read-only and copy any differences, then change anything that uses it to point to the new server.

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What I would do is setup and configure as much as you can on the new server to mimic the settings on the old server. Then once you are ready to do the switch, change the remaining final settings on the new server and shut down the old server.

If the new server does not perform as expected, turn the old server back on until you figure out what the problem is.

This would be the best way to minimize downtime.

Also, I believe active directory and the windows server OS have tools to export and import configuration settings to make the transition as painless as possible.


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That doesn't really handle the fileshares, but is roughly equivalent to what I wrote. – mfinni Jan 5 '11 at 20:23
You're right mfinni, unfortunately I didn't see the new answer notification before I posted :-x. – byachna Jan 5 '11 at 20:30

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