A Brief History of High Availability

The history of high availability databases can be divided into three categories: Active-passive, Active-Active, and Multi-Active. Active-passive databases have an active node that processes requests with a hot spare ready to go in case of disaster. Active-Active databases have at least two active nodes that shard data and perform writes to the database. Multi-Active databases require at least three active nodes, each capable of performing reads and writes for any data in the cluster without generating conflicts. The development of these systems has been driven by the need for increased availability, scalability, and consistency in modern distributed computing environments.