AWS Certified Solutions Architect – Professional — Question 966

An ERP application is deployed across multiple AZs in a single region. In the event of failure, the Recovery Time Objective (RTO) must be less than 3 hours, and the Recovery Point Objective (RPO) must be 15 minutes. The customer realizes that data corruption occurred roughly 1.5 hours ago.
What DR strategy could be used to achieve this RTO and RPO in the event of this kind of failure?

Answer options

• A. Take hourly DB backups to S3, with transaction logs stored in S3 every 5 minutes.
• B. Use synchronous database master-slave replication between two availability zones.
• C. Take hourly DB backups to EC2 Instance store volumes with transaction logs stored In S3 every 5 minutes.
• D. Take 15 minute DB backups stored In Glacier with transaction logs stored in S3 every 5 minutes.

Correct answer: A

Explanation

To recover from a data corruption event that happened 1.5 hours ago, point-in-time recovery is required, which rules out synchronous replication (Option B) since the corruption would have replicated instantly. EC2 Instance Store (Option C) is ephemeral and unsafe for backups, while Glacier (Option D) retrieval times would exceed the 3-hour RTO. Storing hourly backups and 5-minute transaction logs in S3 (Option A) allows restoring to a point just before the corruption within the 15-minute RPO and 3-hour RTO.