How to distinguish a standard AWS database from a Multi-AZ deployment and what are the main differences?

AWS standard database (e.g., RDS) is usually deployed in a single Availability Zone (AZ). In this case, all load and data are located in one data center.

A Multi-AZ deployment is a configuration where the database is automatically replicated to another AZ. Main differences:

• Reliability and fault tolerance: Multi-AZ provides automatic failover to a backup in another AZ in case of failure, minimizing downtime.
• Backup: Multi-AZ replication is synchronous, so data is always up-to-date.
• Performance: In Multi-AZ, the primary load is on the main database, and the standby is used only during failure.

Thus, Multi-AZ deployment is suitable for critical applications where high availability and minimal downtime are essential.