Availability, scaling & operations
Amazon RDS read replicas vs Read replicas (PostgreSQL, MySQL)
RDS read replicas map to read replicas in Azure Database for PostgreSQL and MySQL.
Both use asynchronous native replication, can sit in another region, and can be promoted.
Side-by-side comparison
| Aspect | Amazon Web Services | Microsoft Azure |
|---|---|---|
| Service | Amazon RDS read replicas | Read replicas (PostgreSQL, MySQL) |
| Lifecycle | Generally available | Generally available |
| What it is | Asynchronous read-only copies in the same or another Region, which can be promoted to standalone instances. | Asynchronous read-only replicas in the same or another region, which can be promoted, with virtual endpoints for PostgreSQL. |
| Pricing model | Each replica is billed as a DB instance, plus cross-Region data transfer. | Each replica is billed as a server (compute and storage), plus cross-region data transfer. |
| Docs | Amazon RDS read replicas docs | Read replicas (PostgreSQL, MySQL) docs |
| Pricing page | Amazon RDS read replicas pricing | Read replicas (PostgreSQL, MySQL) pricing |
| Exams | SAA-C03 SOA-C03 | AZ-305 |
Key differences
- Endpoints. Azure PostgreSQL has virtual endpoints that keep stable writer and reader hostnames through promotion. On RDS you repoint the application or use Route 53 or RDS Proxy.
- Promotion. Azure PostgreSQL can promote a replica to be the new primary (with matching tier and storage) or to an independent server. RDS promotes a replica to a standalone instance.
Pricing summary
Pricing models only. No prices are quoted because they change by region and over time.
- AWS
- Each replica is billed as a DB instance, plus cross-Region data transfer. Amazon RDS read replicas pricing →
- Azure
- Each replica is billed as a server (compute and storage), plus cross-region data transfer. Read replicas (PostgreSQL, MySQL) pricing →
Certification exam mapping
| Exam | Provider | Level | Status |
|---|---|---|---|
| AWS Certified Solutions Architect – Associate SAA-C03 | AWS | Associate | current Italian version retires after Dec 31, 2026. |
| AWS Certified CloudOps Engineer – Associate SOA-C03 | AWS | Associate | current Replaces AWS Certified SysOps Administrator – Associate (SOA-C02), whose last exam day was Sep 29, 2025. Simplified Chinese and Korean versions retire after Nov 19, 2026. |
| Microsoft Certified – Azure Solutions Architect Expert AZ-305 | Azure | Expert | current English version updated Apr 17, 2026. |
Relevance is based on each exam's published scope, not a line-by-line objective match. Check the official study guide.
FAQ
What is the Azure equivalent of Amazon RDS read replicas?
RDS read replicas map to read replicas in Azure Database for PostgreSQL and MySQL. Both use asynchronous native replication, can sit in another region, and can be promoted.
How does pricing compare between Amazon RDS read replicas and Read replicas (PostgreSQL, MySQL)?
AWS: Each replica is billed as a DB instance, plus cross-Region data transfer. Azure: Each replica is billed as a server (compute and storage), plus cross-region data transfer. Check the official pricing pages for current rates.
Which certification exams cover this topic?
AWS Certified Solutions Architect – Associate (SAA-C03); AWS Certified CloudOps Engineer – Associate (SOA-C03); Microsoft Certified – Azure Solutions Architect Expert (AZ-305).