What is Redis Sentinel failover and how does it work?

What is Redis Sentinel failover and how does it work?

Redis Sentinel is a system designed to manage Redis instances, providing high availability and monitoring. Failover occurs when the master node fails, and Sentinel promotes a replica to master.

How does Sentinel detect a master failure?

Sentinel uses a voting mechanism to determine if a master is down. It sends periodic PING commands to the master and replicas. If it doesn't receive a response after a certain threshold, it considers the master as failed.

What happens during the failover process?

During failover, Sentinel promotes one of the replicas to master and updates the configuration of other replicas to point to the new master. It also notifies clients about the change.

Can I configure multiple Sentinels for redundancy?

Yes, you can configure multiple Sentinel instances to ensure redundancy. This way, if one Sentinel fails, others can still monitor the Redis instances.