A Multi-AZ deployment in Amazon RDS involves creating a primary database instance and automatically replicating it to a secondary instance in another Availability Zone (AZ). This provides high availability, fault tolerance, and automatic failover. In contrast, a Single-AZ deployment has only one database instance in a single AZ, which is more cost-effective but lacks redundancy.
Benefits of Multi-AZ :
1. Enhanced durability : Data is synchronously replicated across AZs, reducing data loss risk.
2. Automatic failover : If the primary instance fails, RDS switches to the secondary instance with minimal downtime.
3. Maintenance impact reduction : Updates or backups on the primary instance don’t affect the secondary instance.
Benefits of Single-AZ :
1. Cost savings : Requires fewer resources, making it cheaper than Multi-AZ deployments.
2. Simplicity : Easier to set up and manage due to having only one instance.
3. Suitable for non-critical applications : Ideal for development, testing, or applications that can tolerate some downtime.
