What is redundancy and why is it used in distributed system?

Redundancy in distributed systems refers to the duplication of critical components or data to ensure reliability and availability. It is used to prevent single points of failure, allowing the system to continue operating smoothly even if some components fail. By having multiple instances of data or services, redundancy enhances fault tolerance and improves overall system resilience, ensuring that users experience minimal disruption. This is crucial in environments where uptime and data integrity are paramount.