Also probably not the case. In most cases, systems can scale reads with replicas and queue writes to a write instance. You can also shard if write throughput

Also probably not the case. In most cases, systems can scale reads with replicas and queue writes to a write instance. You can also shard if write throughput needs to be higher. Many of the most popular services scaled this way before (if even) adopting more complex solutions. StackOverflow[0] and Pinterest[1] are examples. You can scale your database beyond n=1 in different ways without scaling fully independent, isolated instances. [0] https://highscalability.com/stack-overflow-architecture/ https://highscalability.com/stack-overflow-architecture/ [1] https://highscalability.com/scaling-pinterest-from-0-to-10s-of-billions-of-page-views-a/ https://highscalability.com/scaling-pinterest-from-0-to-10s-...