Amazon ElastiCache
- ElastiCache manage Redis or Memcached.
 - Using ElastiCache involves heavy code changes.
 
| Redis | Memcached | 
|---|---|
| Multi AZ with failover | Multi-Node for sharding | 
| Read replicas to scale reads; high availability | No high availability | 
| Data durability | Non persistent | 
| Supports sets and sorted sets | Multi-threaded architecture | 
Cache Security
- Supports IAM Authentication for Redis.
 - IAM policies on ElastiCache are only used for AWS API-level security.
 - Redis AUTH
- Set password/token, Supports SSL in flight encryption.
 
 - Memcached
- Supports SASL-based authentication
 
 
Patterns for ElastiCache
- Lazy Loading: all read data is cached which becomes stale.
 - Write Through: adds/updates data when written to DB.
 - Session Store: store temporary session data.