SOA-C02 Reliability and Business Continuity Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✓

  Enable Multi-AZ on the RDS instance.

  Why this is correct

  Enable Multi-AZ on the RDS instance: Multi-AZ creates a synchronous standby replica in a different Availability Zone. When the primary DB instance fails or its Availability Zone becomes unavailable, Amazon RDS automatically flips the DNS record to the standby, providing rapid, automated failover. This directly addresses the high availability requirement for the web application's database layer by eliminating a single point of failure.

• ✗

  Take a manual snapshot every hour.

  Why it's wrong here

  Take a manual snapshot every hour: While manual snapshots provide a backup up to the previous hour, they are not an automated high availability solution. Restoring from a snapshot requires a manual process to create a new DB instance, which can take minutes and results in extended downtime. The hourly RPO is acceptable only for backup/recovery, not for minimizing service interruption during an infrastructure failure.

• ✗

  Create a read replica in a different Region.

  Why it's wrong here

  Create a read replica in a different Region: A cross-Region read replica replicates data asynchronously to a different geographic area, but it is designed for read scaling and disaster recovery. Promoting a read replica to become the primary DB instance is a manual operation, and replication lag can cause data loss. It does not provide automatic, synchronous failover within the same Region, which is what Multi-AZ offers.

• ✓

  Configure automated backups with a retention period of 30 days.

  Why this is correct

  Configure automated backups with a retention period of 30 days: Automated backups enable point-in-time recovery to any second within the retention window, protecting against logical data corruption or accidental deletes. However, restoring from an automated backup is a manual action that creates a brand-new DB instance, so it cannot provide automatic database failover. This is a complement to Multi-AZ, not a replacement for high availability.

• ✗

  Increase the DB instance class to the largest available.

  Why it's wrong here

  Increase the DB instance class to the largest available: Scaling to a larger instance class increases compute and memory capacity, which can improve transaction processing performance under load. It does not, however, add any redundancy; the DB instance remains a single point of failure on one host in one Availability Zone. High availability requires replication and automated failover, not simply more powerful hardware.

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