Interview › Databases & Caching
What is Redis Sentinel, and what does it provide?
Databases & Caching · Advanced level
Answer
Redis Sentinel monitors a primary-replica deployment, detects primary failure, elects a new primary, and provides discovery. It gives failover but not sharding.
Technical explanation
Sentinel monitors Redis primary and replicas and decides failover through quorum.
It promotes a replica and tells Sentinel-aware clients where the new primary is.
It does not shard data; it is an HA mechanism for a non-clustered dataset.
Hands-on example
Sentinel failover flow:
1. Sentinels detect primary down.
2. Quorum agrees.
3. A leader selects a replica.
4. Replica is promoted.
5. Other replicas follow it.
6. Clients reconnect through Sentinel discovery.
Check how well your resume matches the role with our free resume checker— match score, ATS check, and the skills you're missing.
More Databases & Caching interview questions
- What is Amazon RDS, and what does it manage for you versus self-managed databases?
- What database engines does RDS support?
- What is the difference between RDS and Aurora?
- What is Multi-AZ in RDS, and how does automatic failover work?
- How long does an RDS Multi-AZ failover typically take, and what triggers it?
- What is the difference between Multi-AZ and a read replica?
- When would you use a read replica, and can it become a standalone database?
- Can a read replica be in a different region, and why would you do that?