Understanding replicas and multi-AZ
Many database deployments require high availability or a failover strategy to meet the recovery point objectives (RPOs) and recovery time objectives (RTOs) of the application. RDS offers two different solutions to meet those requirements:
- Multi-AZ deployments
- Read replicas
Both of these technologies offer enhanced protection from a primary database failing and will speed up any database recovery strategy, but they use different methods and have different use cases.
Multi-AZ
In Chapter 3, Understanding AWS Infrastructure, we learned about AWS infrastructure, VPCs, and Availability Zones (AZs). A Multi-AZ deployment is one in which you provision a primary database in one AZ and standby databases in one or more different AZs. The primary and standby databases are kept synchronized either using their native replication technology (Always On for SQL Server, for example) or by using an AWS-specific technology. The syncing process...
