MemoryDB

aws/database aws/service

💡 Definition

Amazon MemoryDB for Redis is a Redis-compatible, durable, in-memory database service that delivers ultra-fast performance.

🔑 Key Concepts

In-Memory Speed: Microsecond read and single-digit millisecond write latency.
Durability: Unlike ElastiCache (which is a cache), MemoryDB persists data across Multi-AZs using a distributed transactional log.
Redis Compatible: Works with existing Redis tools and code.

⚙️ How it Works

It acts as a primary database (not just a cache). It stores data in memory for speed but also writes to a durable transaction log across multiple AZs to ensure data is not lost if a node fails.

🎯 Use Cases

Microservices: Backend for high-performance microservices.
Gaming: Leaderboards, player state.
IoT: Real-time device data.

💰 Pricing Model

Data stored: Charged per GB-month.
Data written: Charged per GB written.

📝 Exam Tips (CLF-C02)

Keyword: "Redis-compatible, durable, in-memory database".
Difference from ElastiCache: Durability (MemoryDB is a primary DB, ElastiCache is a cache/ephemeral).

See Also: * ElastiCache * DynamoDB