Amazon ElastiCache

Core Characteristics

• In-memory data store service

• Faster than disk-based databases like DynamoDB

• Push-button scalability for:

  • Memory

  • Writes

  • Reads

• Pricing based on node size and usage hours

Engine Types

Memcached

• No-frills, robust workhorse

• Simple architecture

• Basic caching solution

• Non-persistent by design

Redis

• Feature-rich option

• Optional backup and persistence capabilities

• More complex architecture

• Advanced features and data structures

• Not meant to replace persistent databases (RDS, DynamoDB)

Common Use Cases

1. Web Session Storage

   • Centralized session management for web server fleets

   • Alternative to multicast in VPC environments

   • Prevents session loss during server failures

2. Database Enhancement

   • Offload work from MySQL instances

   • Reduce database engine size requirements

   • Cost optimization potential

3. Real-time Applications

   • Gaming leaderboards

   • Mobile applications

   • Factory floor data streaming

   • Real-time dashboard support

Key Considerations

• Primary purpose is caching, not persistent storage

• Extremely fast due to in-memory storage

• Trade-off between speed and persistence

• Should complement, not replace, persistent databases