The answer is that automated backups must be enabled on the source DB instance. This is required because Amazon RDS for MySQL uses binary logs from automated backups to stream changes to a read replica in another Region; without a backup retention period of at least 1 day, the source cannot generate the necessary logs for cross-region replication. On the AWS Certified Database Specialty DBS-C01 exam, this concept tests your understanding that cross-region replication is built on top of the automated backup mechanism, not just manual snapshots. A common trap is assuming that only manual snapshots or Multi-AZ are prerequisites, but the exam emphasizes that automated backups with a minimum retention period are the foundational requirement. Remember the memory tip: “Backups first, then replication” — if you cannot restore, you cannot replicate across Regions.
DBS-C01 Management and Operations Practice Question
This DBS-C01 practice question tests your understanding of management and operations. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Which THREE of the following are required to set up cross-Region replication for an Amazon RDS for MySQL DB instance? (Choose THREE.)
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The backup retention period on the source must be at least 1 day.
Option A is correct because Amazon RDS requires a minimum backup retention period of 1 day on the source DB instance to enable automated backups, which are necessary for cross-Region replication. The backup retention period determines how long automated backups are retained, and a value of at least 1 day ensures that the source instance can generate the binary logs needed for replication to a read replica in another Region.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
The backup retention period on the source must be at least 1 day.
Why this is correct
Backup retention must be at least 1 day to enable automated backups.
Related concept
Read the scenario before looking for a memorised answer.
✗
The source DB instance must be in a VPC.
Why it's wrong here
The instance can be in EC2-Classic, but it is recommended to be in a VPC. However, it is not a strict requirement.
✓
A read replica must be created in the target Region.
Why this is correct
A read replica is the mechanism for cross-Region replication.
Related concept
Read the scenario before looking for a memorised answer.
✓
Automated backups must be enabled on the source DB instance.
Why this is correct
Automated backups are required for replication.
Related concept
Read the scenario before looking for a memorised answer.
✗
The source DB instance must be a Multi-AZ deployment.
Why it's wrong here
Multi-AZ is not required for cross-Region replication.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often assume Multi-AZ is required for cross-Region replication, but Multi-AZ is only for high availability within a single Region, not for cross-Region replication, which relies on automated backups and read replicas.
Detailed technical explanation
How to think about this question
Cross-Region replication for Amazon RDS MySQL uses asynchronous replication based on binary log (binlog) file position or GTID-based replication. The source instance must have automated backups enabled to generate and retain binlogs, which are then streamed to the read replica in the target Region. The backup retention period of at least 1 day ensures that binlogs are not purged before the replica can catch up, especially during network interruptions or lag.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A healthcare organisation deploys an application with a public-facing web tier and a private database tier. The database subnet has no public IP and only accepts connections from the web tier's security group. Questions like this test whether you can design cloud network isolation using VNets/VPCs, subnets, and security group rules.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Management and Operations — This question tests Management and Operations — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The backup retention period on the source must be at least 1 day. — Option A is correct because Amazon RDS requires a minimum backup retention period of 1 day on the source DB instance to enable automated backups, which are necessary for cross-Region replication. The backup retention period determines how long automated backups are retained, and a value of at least 1 day ensures that the source instance can generate the binary logs needed for replication to a read replica in another Region.
What should I do if I get this DBS-C01 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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