In the Hot-Hot system, both the data centers are active at the same time and serve the user's traffic. Here, we employ several CDN and geolocation techniques to route the user to a given data center.
The challenge we face in doing so is that if one region goes completely blank, the other region should have enough headroom to ensure that traffic for the other region is absorbed
The advantage of employing this system is that the user experience is a good one, as in this design the users are routed to the nearest system
