In the next diagram I'm trying to have a backup web page in another datacenter and a service like DynDNS that controls failovers in SERVER A to switch to SERVER B. But, what happens if DynDNS fails?
What is more probably, that DATACENTER A fails or DynDNS fails and make both unreachable? DynDNS has replicated controls in different datacenters?
P.D.: I'm using DynDNS as example.