AWS Certified Solutions Architect – Associate (SAA-C03) — Question 527

A company has a regional subscription-based streaming service that runs in a single AWS Region. The architecture consists of web servers and application servers on Amazon EC2 instances. The EC2 instances are in Auto Scaling groups behind Elastic Load Balancers. The architecture includes an Amazon Aurora global database cluster that extends across multiple Availability Zones.

The company wants to expand globally and to ensure that its application has minimal downtime.

Which solution will provide the MOST fault tolerance?

Answer options

• A. Extend the Auto Scaling groups for the web tier and the application tier to deploy instances in Availability Zones in a second Region. Use an Aurora global database to deploy the database in the primary Region and the second Region. Use Amazon Route 53 health checks with a failover routing policy to the second Region.
• B. Deploy the web tier and the application tier to a second Region. Add an Aurora PostgreSQL cross-Region Aurora Replica in the second Region. Use Amazon Route 53 health checks with a failover routing policy to the second Region. Promote the secondary to primary as needed.
• C. Deploy the web tier and the application tier to a second Region. Create an Aurora PostgreSQL database in the second Region. Use AWS Database Migration Service (AWS DMS) to replicate the primary database to the second Region. Use Amazon Route 53 health checks with a failover routing policy to the second Region.
• D. Deploy the web tier and the application tier to a second Region. Use an Amazon Aurora global database to deploy the database in the primary Region and the second Region. Use Amazon Route 53 health checks with a failover routing policy to the second Region. Promote the secondary to primary as needed.

Correct answer: D

Explanation

Option D is correct because Amazon Aurora global database provides low-latency cross-region replication and allows for quick promotion of the secondary database to primary with minimal RTO and RPO during a disaster. Option A is incorrect because Auto Scaling groups are regional resources and cannot span across multiple AWS Regions. Options B and C are less effective because they rely on cross-region read replicas or AWS DMS, which do not match the performance, simplicity, and low replication latency offered natively by Aurora global databases.