Amazon ElastiCache is a fully managed in-memory caching service that supports:
-
Redis (most popular)
- Memcached
✅ It provides ultra-fast data retrieval, low latency, and high throughput — ideal for real-time applications.
🧠 Why Use ElastiCache?
- Reduce latency by caching frequently accessed data
- Improve application performance
- Offload read pressure from databases like RDS, Aurora
- Enable session storage, leaderboards, pub/sub systems, and real-time analytics
🆚 Redis vs Memcached
| Feature |
Redis |
Memcached |
| Data Types |
Strings, Hashes, Lists, Sets |
Strings only |
| Persistence |
✅ Yes |
❌ No |
| Pub/Sub |
✅ Yes |
❌ No |
| Replication |
✅ Yes |
❌ No |
| Clustering |
✅ Yes (sharding + HA) |
✅ Yes (sharding only) |
| Use Case |
Real-time analytics, queues |
Simple cache |
🔧 Key Features
| Feature |
Description |
| Fully Managed |
AWS handles patching, backups, scaling |
| Multi-AZ with Failover |
For Redis (with automatic failover) |
| Automatic Backups |
For Redis (snapshot-based) |
| Scaling |
Cluster mode for horizontal scaling (Redis only) |
| Monitoring |
CloudWatch integration |
| Security |
VPC, IAM, KMS encryption, SSL |
🧰 Common Use Cases
| Use Case |
Description |
| Caching DB queries |
Cache frequently read data from RDS/Aurora |
| Session management |
Store user session data for web apps |
| Leaderboard systems |
Use sorted sets in Redis |
| Pub/Sub messaging |
Real-time chat, notifications |
| Token and auth caching |
Reduce load on authentication systems |
🏗️ Architecture Diagram (Simplified)
🛡️ Security & Access
- Deploy in VPC
- Use Security Groups to restrict access
-
Encryption in-transit (TLS) and at-rest (KMS)
- Use AUTH token for Redis authentication
💸 Pricing Highlights
| Cost Factor |
Notes |
| Instance Hours |
Based on node type and size (on-demand or reserved) |
| Data Transfer |
Free within same AZ |
| Backups |
Only for Redis (snapshot storage charged per GB) |
👉 ElastiCache Pricing
🧪 Redis CLI Example
✅ Summary
| Attribute |
ElastiCache |
| Engine Support |
Redis, Memcached |
| Management |
Fully managed by AWS |
| Scaling |
Vertical + Horizontal (Redis Cluster) |
| Use Cases |
Caching, session store, queues, analytics |
| Security |
VPC, IAM, encryption, access control |
