Availability, scaling & operations
Amazon RDS Multi-AZ deployments vs Zone-redundant high availability (PostgreSQL, MySQL, Azure SQL)
RDS Multi-AZ deployments map to zone-redundant high availability in Azure Database for PostgreSQL and MySQL, and to the zone-redundant configurations of Azure SQL Database and Managed Instance.
Side-by-side comparison
| Aspect | Amazon Web Services | Microsoft Azure |
|---|---|---|
| Service | Amazon RDS Multi-AZ deployments | Zone-redundant high availability (PostgreSQL, MySQL, Azure SQL) |
| Lifecycle | Generally available | Generally available |
| What it is | Synchronous standby in another AZ with automatic failover (Multi-AZ DB instance), or a Multi-AZ DB cluster with two readable standbys for MySQL and PostgreSQL. | Synchronous standby (PostgreSQL, MySQL) or multiple replicas (SQL Database Business Critical and Hyperscale), placed in another zone, with automatic failover. |
| Pricing model | Multi-AZ roughly doubles instance cost (the standby is billed), plus storage for each copy. | The standby is billed like the primary server (compute and storage). In Azure SQL, zone redundancy may add a premium depending on the tier. |
| Docs | Amazon RDS Multi-AZ deployments docs | Zone-redundant high availability (PostgreSQL, MySQL, Azure SQL) docs |
| Pricing page | Amazon RDS Multi-AZ deployments pricing | Zone-redundant high availability (PostgreSQL, MySQL, Azure SQL) pricing |
| Exams | SAA-C03 SOA-C03 | DP-300 AZ-305 |
Key differences
- Readable standbys. RDS Multi-AZ DB clusters (MySQL and PostgreSQL) have two readable standbys. Azure PostgreSQL and MySQL standbys aren't readable. Azure SQL Business Critical includes a free readable secondary.
- Same-zone option. Azure PostgreSQL and MySQL also offer same-zone HA, where the standby is in the same zone, for lower latency in regions or setups without zone redundancy.
- Aurora. Aurora's storage is already spread across three AZs, and any replica can become the writer. Azure's closest match is HorizonDB (preview) or SQL Database Hyperscale.
Pricing summary
Pricing models only. No prices are quoted because they change by region and over time.
- AWS
- Multi-AZ roughly doubles instance cost (the standby is billed), plus storage for each copy. Amazon RDS Multi-AZ deployments pricing →
- Azure
- The standby is billed like the primary server (compute and storage). In Azure SQL, zone redundancy may add a premium depending on the tier. Zone-redundant high availability (PostgreSQL, MySQL, Azure SQL) 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 Database Administrator Associate DP-300 | Azure | Associate | current English version will be updated on Oct 27, 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 Multi-AZ deployments?
RDS Multi-AZ deployments map to zone-redundant high availability in Azure Database for PostgreSQL and MySQL, and to the zone-redundant configurations of Azure SQL Database and Managed Instance.
How does pricing compare between Amazon RDS Multi-AZ deployments and Zone-redundant high availability (PostgreSQL, MySQL, Azure SQL)?
AWS: Multi-AZ roughly doubles instance cost (the standby is billed), plus storage for each copy. Azure: The standby is billed like the primary server (compute and storage). In Azure SQL, zone redundancy may add a premium depending on the tier. 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 Database Administrator Associate (DP-300); Microsoft Certified – Azure Solutions Architect Expert (AZ-305).