RDS Basics
- Managed service: automated patching, backups, monitoring.
- Engines: MySQL, PostgreSQL, MariaDB, Oracle, SQL Server, Db2.
- Max storage: 64 TB (varies by engine).
- Automated backups: 0–35 days retention. Point-in-time recovery.
- Manual snapshots: kept until explicitly deleted.
High Availability
- Multi-AZ: synchronous standby in another AZ. Automatic failover.
- Multi-AZ is NOT for read scaling — it is for high availability only.
- Read Replicas: asynchronous replication. Up to 15 for Aurora, 5 for others.
- Read Replicas can be cross-region for disaster recovery.
- Read Replicas can be promoted to standalone databases.
Aurora
- MySQL and PostgreSQL compatible. 5x faster than MySQL, 3x faster than PostgreSQL.
- 6 copies of data across 3 AZs. Self-healing storage.
- Aurora Serverless: auto-scales capacity. Pay per ACU-second.
- Aurora Global Database: <1 second cross-region replication.
- Auto-scaling read replicas based on CPU/connections.
Security
- Encryption at rest: KMS. Must be enabled at creation.
- Encryption in transit: SSL/TLS.
- IAM database authentication for MySQL and PostgreSQL.
- Cannot encrypt an unencrypted DB — snapshot, copy with encryption, restore.
Practice RDS Questions
Put your knowledge to the test with practice questions.