How Uber Scaled Cassandra for Tens of Millions of Queries Per Second?

Uber's Cassandra database service supports tens of millions of queries per second, petabytes of data, and tens of thousands of nodes, ensuring high reliability and low latency for mission-critical workloads. The dedicated Cassandra team manages daily operations, implements new features, and ensures 99.99% availability. Uber's custom framework and service discovery mechanisms enable efficient lifecycle management and real-time node discovery. Key challenges tackled include unreliable node replacement, lightweight transaction errors, and data inconsistency issues, which were addressed through various engineering improvements.