We have just setup our server (although I may be reinstalling it from scratch to use 2008 rather than 2003) and we are now looking into redundancy options. The best option I can see would be to have a duplicate server next to our current one which runs the domain aswell – we can then power off one of the servers for RAM upgrades etc. and the domain will continue to run as normal.
Is this functionality built in to Windows Server 2008? Also, we are using the server as a file server aswell as the domain controller – would this be duplicated across the two servers aswell?
So basically my questions are:
How easy would it be to setup a continuously duplicated server next to our current server?
Would we just need another server license for 2008, or another CAL license for each device?
Thanks,
Danny
Best Answer
I absolutely agree that the best way to handle this is to simply create another domain controller. Domain services, DNS, etc, will all work fine - very well - with an extra DC. They replicate to each other and if one goes down, no problem.
You will want to make sure that all clients have the primary DC as one of their configured DNS servers (either via static config or DHCP). You also want to make sure that you do not run DHCP on both servers (unless you give them separate scopes) so they don't run into each other. You can of course configure DHCP identically on both boxes and just make sure you start DHCP on the "takeover" box when the primary is down for maintenance, and vice versa.
Finally for high availability of file shares you could look at Windows DFS, which will sync file shares across multiple servers. This is not a backup - if you delete a file on server 1 it gets deleted off server 2 - but it would keep the file contents in synch between both servers. Note that this will NOT (i don't think) automatically transfer a user's connection to a different server - so if a user has a file open on server1 and server1 goes down, the user can access the file on server2, but I believe the user will have to re-open the file.
What I would recommend in this scenario is two domain controllers and putting the file shares on a 3rd server or a NAS. That way, rebooting the DCs doesn't affect file access at all. And, best practice dictates that DCs should only be DCs - no other roles/services running on them.