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How do you monitor Redis/ElastiCache (evictions, memory, latency, hit ratio)?
Databases & Caching · Advanced level
Answer
I monitor Redis or ElastiCache with hit ratio, latency, CPU, memory, evictions, fragmentation, connections, rejected connections, replication lag, slowlog, command stats, and application fallback rate.
Technical explanation
Global hit ratio can hide bad key patterns; monitor by endpoint or key prefix where possible.
Large keys and hot keys can overload a single Redis thread or shard even when total cluster capacity looks fine.
Use SCAN and UNLINK instead of KEYS and mass DEL; restrict dangerous commands through ACLs or operational policy.
Hands-on example
Operational commands:
INFO stats
INFO memory
INFO commandstats
SLOWLOG GET 10
LATENCY LATEST
redis-cli --bigkeys -h <host> -p 6379
Safe cleanup pattern:
redis-cli --scan --pattern "session:*" | while read key; do redis-cli UNLINK "$key"; done
Pipeline warmup in batches instead of one command per network round trip.
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