In this system/design, only one of the regions is active at any time and only in the event of BCP (Business Continuity Planning) do we fall back to the other region.
The challenges we face in using this system are as follows:
- It's easy to forget the other region until the problem comes into play; it's very important to keep using both the regions in sync w.r.t both Data & Software on a continuous basis.
- As only one region is active, the correct failover of users to another data center has to be thought through well
The advantage of employing this system is that all the writes happen in one region which keeps database designs simple.
