Cassandra is a distributed storage system for managing very large amounts of structured data spread out across many commodity servers, while providing highly available service with no single point of failure. Cassandra aims to run on top of an infrastructure of hundreds of nodes (possibly spread across different data centers). At this scale, small and large components fail continuously. The way Cassandra man- ages the persistent state in the face of these failures drives the reliability and scalability of the software systems rely- ing on this service. While in many ways Cassandra resem- bles a database and shares many design and implementation strategies therewith, Cassandra does not support a full rela- tional data model; instead, it provides clients with a simple data model that supports dynamic control over data lay- out and format. Cassandra system was designed to run on cheap commodity hardware and handle high write through- put while not sacrificing read efficiency.