Hi, at Zalando, we are scaling all of our core businesses with PostgreSQL. Depending on your dataset, it can be fairly easy to shard your data for a horizontal scale-out (think of independent customer datasets). We have lots of databases that we scale horizontally to much bigger numbers. But, we also developed several tools that makes working with shards mostly transparent. Did not find a better source but one way we use PostgreSQL can be seen in detail in the following slides: http://gotocon.com/berlin-2013/presentation/Why%20Zalando%20...