In 2015, it was no longer possible to continue buying a larger database server for Shopify. We finally had no choice but to shard the database, which allowed us to horizontally scale our databases and continue our growth. However, what we gained in performance and scalability we lost in resilience. Throughout the Shopify codebase was code like this: Sharding.with_each_shard do some_action end If any of our shards went down, that entire action would be unavailable across the platform. We realized this would become a major problem as the number of shards continued to increase. In 2016 we sat down to reorganize Shopify’s runtime architecture.