SOA-C03 practice question: Restores, versioning, RPO and RTO (1 of 2)

Reliability and Business Continuity A free question from our original SOA-C03 practice exam. Try it, then open the answer to see why each option is right or wrong.

A public library's catalog runs on an Amazon RDS for PostgreSQL DB instance with automated backups kept for 14 days. At 10:42 this morning, a faulty script deleted thousands of loan records. The last manual snapshot was taken yesterday at midnight. The library wants to recover the data as it was just before 10:42, with as little data loss as possible. What should a CloudOps engineer do?

Choose one answer.

A. Restore to 10:41 with point-in-time recovery into a new DB instance, then recover the records from it.
B. Restore yesterday's midnight snapshot to a new DB instance and switch the application to the new instance's endpoint.
C. Perform a point-in-time restore of the existing DB instance in place to 10:41, keeping its current endpoint.
D. Create a read replica of the DB instance and promote it, because the replica still holds the rows the script deleted.

Show the answer and explanation

Answer: A

A. Right: Correct. Automated backups and transaction logs let RDS restore to any second within the retention period. The restore creates a new instance, from which the records can be copied back or which can replace the original. Learn more: Restoring a DB instance to a specified time (opens in a new tab)
B. Wrong: The snapshot is more than 10 hours old, so all changes made this morning before the script ran would be lost. Point-in-time restore gives a much closer recovery point. Learn more: Restoring to a DB instance (opens in a new tab)
C. Wrong: RDS does not restore over an existing DB instance. A point-in-time restore always creates a new DB instance with a new endpoint. Learn more: Restoring a DB instance to a specified time (opens in a new tab)
D. Wrong: A new read replica copies the current data, which already lacks the deleted rows. Replicas protect against instance failure, not against bad writes. Learn more: Working with DB instance read replicas (opens in a new tab)

Explanation

Automated backups give RDS point-in-time recovery to any second within the retention window, typically up to about five minutes before now. A restore always creates a new DB instance, so the team either copies the lost rows back or moves the application to the new endpoint. Snapshots lose more data, and replicas copy the mistake.

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Restoring a DB instance to a specified time

SOA-C03 practice question: Restores, versioning, RPO and RTO (1 of 2)

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