DNS & DHCP
Our ISP had a major power outage last month, and it happens that I've just read their final report on the circumstances and remedial actions. Two of the remedial actions they are putting in place are to move their DHCP service back from a virtual machine and onto a dedicated physical server. Their DNS will go on to two dedicated physical servers in two geographically separate data centres.
The DHCP server is to maximise the speed of getting DHCP running again from a cold start. The DNS server is for the same reason and also to load-balance.
Of course, this is a business decision based on risk versus cost and the business damage to them of failure to adequately server their customers.
