Netflix Uses Cassandra. Instagram Uses PostgreSQL. Twitter Uses Redis. They're All Right.
Netflix writes 3M records/sec. Instagram serves a billion users. Twitter handles 300K timeline reads/sec. Each picked a radically different database — not because one is better, but because their access patterns are fundamentally different. This post reverse-engineers all three architectures and gives you a mental framework for making these decisions yourself.
System DesignDatabasesCassandra
