We have a Server 2012 r2 Datacenter at work along with decent hardware specs. We are thinking about creating a domain for about 75 users. The thing is, even though the server is decent, we have no redundancies and this server will be our ADDS, DNS, Print Server as well as our DHCP. So once we get everyone onto domain, and lets say 3 months later if something happens to the server, no computer will have internet connection until we fix it.
So the question is, what would be the best way to tackle this issue, and how to prevent it from before it even happens?