DOP-C02 Question #122: Real Exam Question with Answer & Explanation

Question

A company manages a web application that runs on Amazon EC2 instances behind an Application Load Balancer (ALB). The EC2 instances run in an Auto Scaling group across multiple Availability Zones. The application uses an Amazon RDS for MySQL DB instance to store the data. The company has configured Amazon Route 53 with an alias record that points to the ALB. A new company guideline requires a geographically isolated disaster recovery (DR) site with an RTO of 4 hours and an RPO of 15 minutes. Which DR strategy will meet these requirements with the LEAST change to the application stack?

Options

• ALaunch a replica environment of everything except Amazon RDS in a different Availability Zone.
• BLaunch a replica environment of everything except Amazon RDS in a different AWS Region. Create
• CLaunch a replica environment of everything except Amazon RDS in a different AWS Region. In the
• DLaunch a replica environment of everything except Amazon RDS in a different AWS Region. Create

Explanation

Explanation

Option D is correct because it involves launching a replica environment in a different AWS Region (providing geographic isolation) with an RDS Read Replica promoted during failover - this satisfies the RPO of 15 minutes through near-real-time replication and the RTO of 4 hours by having infrastructure pre-built and ready to activate with minimal changes to the existing stack.

Why the distractors are wrong:

• Option A fails immediately because it uses a different Availability Zone, not a different AWS Region - this does not meet the requirement for a geographically isolated DR site.
• Option B launches in a different Region but likely relies on a snapshot/backup approach (such as automated RDS snapshots), which cannot reliably achieve an RPO of 15 minutes since snapshots are typically taken every 24 hours.
• Option C is similar to D but likely uses a different Route 53 routing mechanism (e.g., simple failover) or RDS configuration that doesn't align as precisely with the RPO/RTO targets or introduces more complexity.

Memory Tip: Remember "RTO/RPO drives the DR tier" - an RPO of 15 minutes requires continuous replication (Read Replica), not snapshots, and geographic isolation always means a different Region, never just a different AZ. When you see "geographically isolated," immediately eliminate any same-region options.

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