Data Storage

Choose where records live, how they are keyed and queried, and how the store grows past a single machine. Storage is the hardest layer to change later: a wrong data model or shard key calcifies into a scaling ceiling, and getting replication wrong silently serves stale or lost data.

When to reach for this

Any system that persists state: picking SQL vs NoSQL, designing a schema and its access paths, adding indexes, splitting a hot table, distributing data across nodes (sharding/partitioning), adding read replicas, or deciding what to denormalize. Reach here the moment "store the data" needs a concrete key and query shape.