I have a SBS '08 server, and it handles all FSMO roles, and every service known to man. I'm trying to shift those to other computers, but we haven't got the capital for another server. I know Linux is a capable OS and has the ability to run DNS, but I'm not too familiar with linux. How could I set up DNS on linux so that it is a redundant DNS server?
Configuring a Linux BIND server to act as a secondary DNS server to AD is easy. I suggest adding your Linux system to your AD zones as a nameserver, and allowing replication from any nameserver for each zone.
Here's the basic steps:
Install BIND on your Linux system
Configure basic BIND options, add all your zones from AD as shown here:
Repeat this zone configuration for all zones in AD - forward and reverse zones. If you have conditional forwarders, you can set them up like this:
This will not send these conditional forwarder zones to AD, you're just configuring them to be a conditional fowarder on BIND. Same difference.
I also let my BIND server be a caching nameserver for all other domains, so it won't be entirely dependant on AD.
Now start BIND, and give it a few minutes to start replicating. You can now use it as a secondary DNS server, and it can be added to your DHCP options or whatever you need.
I use this type of setup and have seen no problems with it.
if you need to "offload" from the server, then DNS will not be that signifgant. If you have another machine with RAID array, move your file shares to the Linux system using Samba. That will have more of an impact.
Same could be said about Exchange or SQl, but if you move those off what was the purpose of getting SBS...
If you're worried about AD redundancy, sorry but your best bet still is a good offsite backup that is tested.