I specifically looked up how to do something like this ( Can you set a backup ip for your server in DNS? ) and the answer basically was you can't. If i say specify 2 ip addresses could i somehow use a HTTP response header to ignore it temporary (say 5mins) and go to the other IP address? Or maybe i can play dead however i'm unsure how to play dead using nginx. I then would like to be available after my box notice the other box is down and be some kind of readonly server.

I'm sure something like this has been implemented i am just wondering how i might implement it with 2 boxes. I'm sure it isn't very difficult? How might i redirect traffic from a backup box to my main server without modifying the DNS?