A financial institution requires a highly available and fault-tolerant architecture for its core banking application. The application runs on Amazon EC2 instances behind an Application Load Balancer (ALB) and uses Amazon Aurora for its database. The institution needs to ensure that the application can withstand the failure of an entire AWS Availability Zone (AZ) with minimal downtime and no data loss. Which solution provides the necessary resilience for the Aurora database?
- ADeploy Amazon Aurora with multiple reader instances across different Availability Zones.
- BSet up Amazon RDS for PostgreSQL with Multi-AZ deployment.
- CEnable Aurora Global Database and replicate to a secondary region.
- DConfigure Amazon Aurora with a single instance in a Multi-AZ deployment.
Show answer & explanationAnswer & explanation
Correct answer: A. Deploy Amazon Aurora with multiple reader instances across different Availability Zones.
Amazon Aurora automatically replicates data across three Availability Zones within a single region, maintaining six copies of your data. Deploying multiple reader instances across different Availability Zones ensures that if one AZ fails, the application can failover to a healthy reader instance or a new writer instance can be promoted with minimal impact and no data loss, as data is already replicated.
Why the other options are wrong
- B. This option is for Amazon RDS for PostgreSQL, not Amazon Aurora, and while Multi-AZ is good, Aurora's architecture with multiple readers offers superior resilience for Aurora.
- C. Aurora Global Database replicates across regions, which is for disaster recovery across regions, not primarily for resilience within a single region against an AZ failure.
- D. A single instance in a Multi-AZ deployment for Aurora is redundant; Aurora inherently replicates data across AZs. However, having multiple reader instances across AZs provides faster failover for read capacity and allows for a quicker promotion of a new writer in case of AZ failure.
Aurora Multi-AZ Resilience
Amazon Aurora provides high availability and fault tolerance within a single region by automatically replicating data across three Availability Zones and supporting multiple reader instances for quick failover.
- Data is replicated 6 ways across 3 AZs.
- Reader instances can be deployed across AZs.
- Automatic failover to a healthy reader or promotion of a new writer.
Memory trick: Aurora's AZ shield, readers spread wide, data's safe, no data hide.