Definition
Fault tolerance is the ability of a system to continue operating without interruption or loss of data when one or more of its components fail. It is achieved through redundancy, where backup components are available to take over immediately if a primary component malfunctions. This ensures high availability and prevents service disruptions, which is critical for business continuity and user satisfaction. For instance, a fault tolerant web server setup might use multiple identical servers behind a load balancer, so if one server crashes, the others seamlessly handle the traffic. This differs from high availability, which aims to minimize downtime but may not guarantee zero interruption. Understanding fault tolerance is essential for cloud architecture and security certifications like AWS Certified Solutions Architect and CCSP.