The answer is that the instance is a read replica and cannot accept write requests. This is because an RDS read replica is designed as a read-only copy of the source database, enforced by the MySQL engine setting the `read_only` parameter to `1` on the replica. The output confirms this by showing the `ReadReplicaSourceDBInstanceIdentifier` field populated, which directly indicates the instance is a read replica and inherently blocks any write operations. On the AWS Certified Database Specialty DBS-C01 exam, this question tests your ability to distinguish between read replica behavior and other common configurations like Multi-AZ, storage encryption, or IOPS limitations—all of which do not make an instance read-only. A frequent trap is confusing Multi-AZ with read replicas, but remember that Multi-AZ only provides failover redundancy, not read-only restrictions. Memory tip: if you see a source instance identifier in the output, think “read-only replica—writes are forbidden.”
DBS-C01 Management and Operations Practice Question
This DBS-C01 practice question tests your understanding of management and operations. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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.
Network Topology
A database specialist sees the above output for an RDS MySQL instance. The application reports that the instance is not accepting writes. What is the most likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The instance is a read replica and cannot accept write requests.
Option B is correct. The output shows the instance is a read replica (ReadReplicaSourceDBInstanceIdentifier is set), which means it is read-only and cannot accept writes. Option A is wrong because Multi-AZ does not affect write capability. Option C is wrong because storage encryption does not prevent writes. Option D is wrong because insufficient IOPS would not make it read-only.
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 instance is a read replica and cannot accept write requests.
Why this is correct
Read replicas are read-only.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
The allocated IOPS are insufficient for the write workload.
Why it's wrong here
Insufficient IOPS would cause performance issues, not a complete write block.
✗
Multi-AZ is not enabled, so the instance cannot accept writes.
Why it's wrong here
Multi-AZ affects availability, not write capability.
✗
Storage encryption is enabled, which prevents write operations.
Why it's wrong here
Storage encryption does not block writes.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
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.
Use explanations to understand the rule behind the answer.
TExam Day Tips
→Underline the problem statement mentally.
→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 media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
What to study next
Got this wrong? Here's your next step.
Identify which DBS-C01 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
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 instance is a read replica and cannot accept write requests. — Option B is correct. The output shows the instance is a read replica (ReadReplicaSourceDBInstanceIdentifier is set), which means it is read-only and cannot accept writes. Option A is wrong because Multi-AZ does not affect write capability. Option C is wrong because storage encryption does not prevent writes. Option D is wrong because insufficient IOPS would not make it read-only.
What should I do if I get this DBS-C01 question wrong?
Identify which DBS-C01 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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This DBS-C01 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the DBS-C01 exam.
Question Discussion
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