Cluster failover in Redis - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is cluster failover in Redis?

Cluster failover in Redis is the process where a replica node automatically takes over as the master if the current master node fails, ensuring continuous availability.

beginner

What role does a replica play during a Redis cluster failover?

During failover, a replica is promoted to master to replace the failed master, allowing the cluster to keep serving requests without interruption.

intermediate

How does Redis detect a master failure in a cluster?

Redis uses a consensus of nodes called a quorum to detect if a master is unreachable or down, triggering failover if confirmed.

intermediate

What is the difference between manual and automatic failover in Redis clusters?

Manual failover requires an administrator to promote a replica, while automatic failover happens automatically when the cluster detects a master failure.

beginner

Why is failover important in a Redis cluster?

Failover ensures high availability by minimizing downtime and data loss when a master node fails, keeping the cluster operational.

What happens during a Redis cluster failover?

A All data is deleted

B The cluster shuts down

C A replica is promoted to master

D The master node restarts automatically

During failover, a replica node is promoted to master to replace the failed master.

How does Redis decide to start a failover?

A When a quorum of nodes agree the master is down

B When a user manually restarts the cluster

C When the master node sends a restart signal

D When the replica nodes are empty

Redis uses a quorum of nodes to detect master failure and trigger failover.

Which node becomes master after failover?

A The old master node

B A replica node

C A random node

D The cluster manager

A replica node is promoted to master during failover.

What is NOT a benefit of Redis cluster failover?

A Permanent data deletion

B Automatic recovery

C High availability

D Data loss prevention

Failover prevents downtime and data loss; it does not cause permanent data deletion.

Manual failover in Redis requires:

A No human intervention

B Automatic detection of failure

C A quorum of nodes

D An administrator to promote a replica

Manual failover requires an administrator to promote a replica to master.

Explain how Redis cluster failover works and why it is important.

Think about what happens when the master node stops working and how the cluster keeps running.

Describe the difference between manual and automatic failover in Redis clusters.

Consider who or what triggers the failover.