Interview › Databases & Caching
How does ElastiCache provide high availability and automatic failover?
Databases & Caching · Advanced level
Answer
ElastiCache provides HA through replication groups, Multi-AZ replicas, node health monitoring, automatic failover, and endpoint updates. Applications still need reconnect and retry behavior during failover.
Technical explanation
ElastiCache uses replication groups, replicas, Multi-AZ placement, health checks, and automatic failover.
Cluster-mode enabled deployments fail over per shard.
Applications must handle dropped connections, endpoint updates, and retry behavior.
Hands-on example
Staging test:
Run GET/SET loop with latency measurement.
Trigger test failover.
Monitor CurrConnections, EngineCPUUtilization, ReplicationLag, CacheHitRate, Evictions, and app p95 latency.
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