Amazon MemoryDB for Redis
- What it is
- Redis-compatible, durable, in-memory database.
- Microsecond reads, single-digit millisecond writes.
- The durability point
- Writes are committed to a multi-AZ transaction log before being acknowledged.
- That makes it safe as a primary database, not just a cache.
- Not to be confused with
- Amazon ElastiCache for Redis — an in-memory cache sitting in front of another database. Fast, but data loss on failure is acceptable by design.
- Amazon DynamoDB — disk-backed NoSQL with millisecond (not microsecond) latency.
- Exam signal
- “In-memory speed and durability, as the system of record” → MemoryDB.
- “Cache in front of RDS to reduce load” → ElastiCache.