AWS Elasticache Memcached

General

• ElastiCache is protocol compliant with Memcached, can use any tool
• Multi-threaded, can take full advantage of multi-core EC2
• Use consistent hashing - add additional nodes to scale horizontally

Scaling and Autodiscovery and Consistent Hashing

• Use for adding new nodes and scaling
• AWS automatically repairs or replaces a cache node, the Domain Name Service (DNS) name of the cache node will remain the same

Best Practices

• Always apply a time to live (TTL) to all of your cache keys, except those you are updating by write-through caching (avoids bugs, the cache key will auto-expire and get refreshed).
• When in doubt, just delete a cache key if you're not sure whether it's affected by a given database update or not. Your lazy caching foundation will refresh the key when needed.
• Pre-warm cache with script or by hitting the url
• To avoid thundering herd problem, add some randomness to your TTL:  ttl = 3600 + (rand() * 120) /* +/- 2 minutes */