Master Redis: 100 Questions to Ace Your Senior-Level Interview

Basic Redis Questions

1. What is Redis, and how does it differ from traditional databases?
2. Explain the key features of Redis.
3. What data structures are supported by Redis?
4. What is the use case for Redis as a caching layer?
5. How does Redis achieve high performance?
6. What are persistent options in Redis?
7. Explain the difference between Memcached and Redis.
8. How is data stored in Redis memory?
9. What is the Redis CLI, and how is it used?
10. Explain the publish/subscribe model in Redis.

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Data Structures

1. What is a String in Redis, and how is it used?
2. How does Redis handle Hash data structures?
3. What are Lists in Redis, and how do you manipulate them?
4. Explain Sets and their operations in Redis.
5. What is a Sorted Set, and when should it be used?
6. How do HyperLogLogs work in Redis?
7. What are Streams in Redis?
8. What is the difference between Hashes and JSON objects in Redis?
9. What is Bitmaps in Redis, and how are they used?
10. Explain the use of Geospatial data types in Redis.

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Persistence and Backup

1. How does Redis handle persistence?
2. What is the RDB snapshot mechanism in Redis?
3. What is AOF (Append-Only File), and how does it work?
4. Compare RDB vs. AOF persistence in Redis.
5. How do you take backups in Redis?
6. How do you configure persistence policies?
7. Explain lazy loading and startup time differences between RDB and AOF.
8. What is AOF rewrite, and why is it important?
9. How does Redis handle data recovery after a crash?
10. What happens if both RDB and AOF are enabled?

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Cluster Management

1. What is Redis clustering, and why is it needed?
2. How does Redis handle sharding in a cluster?
3. What is a Redis hash slot?
4. How are keys distributed across a Redis cluster?
5. How does Redis manage failover in a cluster?
6. What is the role of a master node in Redis?
7. How does a replica node work in Redis?
8. Explain the concept of read replicas.
9. How do you add a new node to a Redis cluster?
10. How does Redis handle node failure in a cluster?

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Replication

1. What is Redis replication, and how does it work?
2. What are replica nodes, and how are they used?
3. Explain asynchronous replication in Redis.
4. How does replica promotion work in Redis?
5. What is partial resynchronization in Redis replication?
6. How does Redis manage replica synchronization?
7. What happens if a master node fails in Redis replication?
8. How do you configure replica-only reads?
9. Can you create a chain of replicas in Redis?
10. What is the role of the replica-priority parameter?

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Performance Optimization

1. How do you optimize Redis for write-heavy workloads?
2. How do you optimize Redis for read-heavy workloads?
3. What is connection pooling, and how does Redis handle it?
4. How do you manage memory consumption in Redis?
5. What are LRU (Least Recently Used) eviction policies?
6. Explain the lazy free mechanism in Redis.
7. How does Redis handle pipeline operations?
8. What is the role of Redis Sentinel in performance tuning?
9. How do you handle large datasets in Redis?
10. What are some tools for monitoring Redis performance?

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Redis Sentinel

1. What is Redis Sentinel, and why is it important?
2. How does Sentinel provide high availability?
3. What is the Sentinel quorum?
4. How does Sentinel detect a master failure?
5. Explain the concept of failover in Redis Sentinel.
6. What are the advantages and limitations of Sentinel?
7. How do you configure a Redis Sentinel cluster?
8. What happens during a failover event in Sentinel?
9. Can Sentinel manage replica promotion?
10. How do you monitor Sentinel events?

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Use Cases and Integration

1. What are the common use cases for Redis?
2. How would you use Redis for session storage?
3. How do you implement caching with Redis?
4. How does Redis handle rate limiting?
5. How do you use Redis as a message broker?
6. What is a common use case for Redis Streams?
7. How can you implement a leaderboard using Redis?
8. How does Redis handle distributed locking?
9. How can Redis integrate with Apache Kafka?
10. How does Redis work with Docker and Kubernetes?

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Security and Authentication

1. How do you secure a Redis deployment?
2. What is password authentication in Redis?
3. How does Redis handle SSL/TLS encryption?
4. What is the protected mode in Redis?
5. How do you restrict access to specific IP addresses in Redis?
6. Explain ACLs (Access Control Lists) in Redis.
7. How do you monitor unauthorized access in Redis?
8. How do you encrypt data at rest in Redis?
9. How do you implement client-side encryption with Redis?
10. What tools are available to audit Redis security?

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Troubleshooting and Debugging

1. How do you debug memory leaks in Redis?
2. How do you troubleshoot latency issues?
3. What are common causes of Redis connection timeouts?
4. How do you monitor expired keys in Redis?
5. What tools can you use to profile Redis queries?
6. How do you identify and fix slow commands in Redis?
7. What are Redis logs, and how do you analyze them?
8. How do you recover from a Redis cluster split-brain?
9. How do you handle OOM (Out of Memory) errors in Redis?
10. What are best practices for upgrading Redis in production?