Database
Amazon RDS
Managed relational databases
Amazon RDS manages relational engines (PostgreSQL, MySQL, MariaDB, Oracle, SQL Server) — handling provisioning, patching, backups, and failover. Multi-AZ gives synchronous standby failover; read replicas scale reads asynchronously.
When to use it
- Relational data with joins, transactions, and SQL access
- Apps needing managed backups, patching, and failover
- Predictable schemas for OLTP workloads
When NOT to use it
- Internet-scale key-value access (use DynamoDB)
- Sub-millisecond in-memory access (use ElastiCache)
- Analytics over petabytes (use Redshift)
Key exam points
- Multi-AZ = HA failover (standby can't serve reads); read replicas = read scaling
- Storage autoscaling grows allocated storage as needed
- Encryption at rest via KMS; in transit via TLS; IAM DB authentication supported for some engines
- Backups: automated with point-in-time recovery to retention window
Compared with
- Amazon Aurora — Aurora is AWS's cloud-native MySQL/PostgreSQL-compatible engine with faster replication and storage autoscaling; RDS covers more engine choices.
- Amazon DynamoDB — DynamoDB is managed NoSQL for key-value at any scale; RDS is relational SQL.