RDS and Database Services
Amazon RDS (Relational Database Service) makes it easy to set up, operate, and scale a relational database in the cloud. It handles routine database tasks like provisioning, patching, backup, recovery, and scaling.
RDS Architecture
┌──────────────────────────────────────────────────────┐
│ RDS DEPLOYMENT │
│ │
│ Single-AZ: Multi-AZ: │
│ ┌────────────┐ ┌────────────┐ │
│ │ Primary │ │ Primary │ │
│ │ Instance │ │ (AZ-a) │ │
│ │ (AZ-a) │ └──────┬─────┘ │
│ └────────────┘ │ Sync │
│ │ Replication │
│ If AZ fails: ┌───────▼─────┐ │
│ Database is DOWN │ Standby │ │
│ │ (AZ-b) │ │
│ └──────┬───────┘ │
│ │ │
│ If primary fails: │
│ Standby becomes new │
│ primary automatically │
└──────────────────────────────────────────────────────┘
Supported Engines
Amazon Aurora: MySQL and PostgreSQL compatible, 5x faster than standard MySQL, 3x faster than PostgreSQL. Automated storage scaling.
MySQL: The world's most popular open-source database. Full AWS management and optimization.
PostgreSQL: Advanced open-source database with strong extensibility and standards compliance.
MariaDB: MySQL-compatible fork with additional features and performance improvements.
Key Features
Automated Backups: Point-in-time recovery up to 35 days. Take snapshots anytime.
Read Replicas: Offload read traffic from the primary instance. Up to 15 replicas with Aurora.
Multi-AZ: Automatic failover to standby in another availability zone.
Performance Insights: Identify database load and optimize slow queries.
Encryption: At rest with KMS, in transit with SSL/TLS.
When to Use RDS vs DynamoDB
┌──────────────────────────┬────────────────────────┐
│ RDS │ DynamoDB │
├──────────────────────────┼────────────────────────┤
│ Complex queries/joins │ Simple key lookups │
│ ACID transactions │ Single-digit ms latency│
│ Schema flexibility: Low │ Schema flexibility: High│
│ Scale: Vertical + reads │ Scale: Unlimited │
│ Cost: Predictable │ Cost: Per request │
└──────────────────────────┴────────────────────────┘