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Management and Operations →hardMultiple ChoiceObjective-mapped

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.

A database administrator is using AWS DMS to migrate an on-premises Oracle database to Amazon RDS for PostgreSQL. The migration has been running for several hours, but the full load phase is taking much longer than expected. The CPU utilization on the DMS replication instance is consistently below 10%. What is the MOST likely cause of the slow performance?

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.

A
The source database has large LOBs that are being transferred in full LOB mode.
Why wrong: Large LOBs can slow migration but would cause higher CPU usage.
B
The target database engine is not compatible with DMS.
Why wrong: DMS supports Oracle to PostgreSQL migration.
C
The DMS task is not configured to use parallel tables.
Why wrong: Parallel load could help, but the symptom suggests target throttling.
D
The target RDS instance is throttling write operations due to low IOPS.
Low IOPS on the target can cause DMS to wait, leading to low CPU on the replication instance.

Full breakdown with real-world context →

Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

✓

The target RDS instance is throttling write operations due to low IOPS.

Option D is correct because when the target RDS instance has insufficient IOPS, write operations are throttled, causing a bottleneck that slows down the full load phase. Even though the DMS replication instance's CPU is low (below 10%), the target database cannot keep up with the incoming data, leading to increased latency and reduced throughput. This is a common performance issue in DMS migrations where the target's provisioned IOPS are exhausted, especially during large data loads.

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 source database has large LOBs that are being transferred in full LOB mode.
Why it's wrong here
Large LOBs can slow migration but would cause higher CPU usage.
✗
The target database engine is not compatible with DMS.
Why it's wrong here
DMS supports Oracle to PostgreSQL migration.
✗
The DMS task is not configured to use parallel tables.
Why it's wrong here
Parallel load could help, but the symptom suggests target throttling.
✓
The target RDS instance is throttling write operations due to low IOPS.
Why this is correct
Low IOPS on the target can cause DMS to wait, leading to low CPU on the replication instance.
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.

Common exam traps

Common exam trap: answer the scenario, not the keyword

The trap here is that candidates often assume slow migration is due to DMS configuration (like LOB mode or parallelism) or source-side issues, but the low CPU on the replication instance is a key indicator that the bottleneck is on the target side, specifically I/O throttling.

Detailed technical explanation

How to think about this question

Under the hood, DMS uses a change data capture (CDC) engine and a full-load mechanism that streams data from the source to the target. When the target RDS instance runs out of IOPS credits (for gp2 volumes) or exceeds its provisioned IOPS limit (for io1/io2), write operations are queued and throttled, causing backpressure on DMS. This manifests as low CPU on the replication instance because DMS is waiting on I/O acknowledgments from the target, not processing data. In real-world scenarios, monitoring the target's 'WriteIOPS' and 'WriteLatency' CloudWatch metrics can confirm this bottleneck.

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 cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.

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.

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FAQ

Questions learners often ask

What does this DBS-C01 question test?

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 target RDS instance is throttling write operations due to low IOPS. — Option D is correct because when the target RDS instance has insufficient IOPS, write operations are throttled, causing a bottleneck that slows down the full load phase. Even though the DMS replication instance's CPU is low (below 10%), the target database cannot keep up with the incoming data, leading to increased latency and reduced throughput. This is a common performance issue in DMS migrations where the target's provisioned IOPS are exhausted, especially during large data loads.

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.

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.