Cassandra

Cassandra is a highly scalable, distributed NoSQL database system designed to handle large amounts of data across many commodity servers without any single point of failure. Originally developed by Facebook and later open-sourced, Cassandra is widely used in environments requiring high availability and fault tolerance.

Developed by Facebook in 2008 to power their inbox search feature, Apache Cassandra became an open-source project under the Apache Software Foundation. Its architecture is designed to manage large volumes of data with minimal latency, making it suitable for real-time data applications. Based on a peer-to-peer distributed system, it ensures no single point of failure, offering continuous availability even when multiple nodes fail. Cassandra employs a masterless ring design, using a gossip protocol to share information about node status, which helps in decentralized and fault-tolerant data distribution. Key features include tunable consistency, column-family data model, and support for ACID properties via lightweight transactions, making it a popular choice for large-scale, mission-critical applications.