Active-Active Against Active-Passive

1. Two Goals That Get Confused

Multi-region is asked for as one thing and is actually two, with different designs and different costs.

• Surviving the loss of a region. An availability goal. The second region exists so that a failure of the first does not end your service.
• Serving distant users faster. A latency goal. The second region exists so that somebody far away is not paying a transcontinental round trip.

They are not the same problem. The first needs a full copy of your write path, ready to take over