All 7 Redis Monitoring & Observability questions
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What key metrics should you monitor to keep track of a Redis instance's overall health? What is the Redis slow log, and how do you use it to identify commands that are taking longer than expected to execute? What third party tools are commonly used for more comprehensive monitoring and visualization of Redis metrics beyond the built-in commands? How do you use the LATENCY command family in Redis to identify specific sources of delay within the server's internal operations? How would you set up proactive alerting for a production Redis instance to catch problems before they significantly impact your application? How would you diagnose a sudden, unexplained increase in Redis latency using the various monitoring tools and commands available?
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Redis › Redis Monitoring & Observability

How do you check the cache hit and miss ratio for a Redis instance being used as a cache, and why does this metric matter?

Beginner

Answer

You check the keyspace_hits and keyspace_misses values from the INFO command, calculating the ratio between them, which tells you what percentage of read requests are being successfully served from the cache versus requiring a more expensive fallback to your primary data source, with a low hit ratio potentially indicating your caching strategy needs improvement.
redis-cli info stats | grep keyspace
Real-world example A team notices their cache hit ratio has dropped significantly after a recent deployment, investigating and discovering a bug that was causing cache keys to be generated inconsistently, preventing successful cache hits.

Common follow-ups: What hit ratio is generally considered healthy for a typical caching workload?;What factors commonly cause a declining hit ratio over time?

Caching Patterns;Redis Performance Tuning & Benchmarking
All 7 Redis Monitoring & Observability questions