The answer is to increase the replication instance size to dms.c4.xlarge (8 GB RAM) because the DMS task is failing due to insufficient memory to handle the large number of LOB columns during the full load phase. When DMS processes LOB columns, it must buffer the entire LOB value in memory for each row, and a dms.c4.large instance with only 4 GB RAM cannot accommodate the combined size of all LOB columns from the 'Orders' table, causing an out-of-memory error. On the AWS Certified Database Specialty DBS-C01 exam, this scenario tests your understanding of DMS resource tuning for LOB migration, specifically that increasing instance memory is the most direct fix for LOB column memory errors, while options like disabling LOB support or adjusting chunk size are traps that either truncate data or fail to address the root cause. Remember the memory tip: "LOB load needs large nodes" — when LOB columns cause memory errors, scale up the instance size first.
DBS-C01 Deployment and Migration Practice Question
This DBS-C01 practice question tests your understanding of deployment and migration. 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 company is migrating a 2 TB on-premises Microsoft SQL Server database to Amazon RDS for SQL Server. The migration must have minimal downtime. The company uses AWS DMS with ongoing CDC. During the full load phase, the DMS task fails with an error indicating that the source table 'Orders' has a large number of LOB columns and the task is running out of memory. The DMS replication instance is a dms.c4.large with 4 GB RAM. The company needs to complete the migration successfully. What should the company do?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Increase the replication instance size to dms.c4.xlarge (8 GB RAM).
Option B is correct because increasing the replication instance size provides more memory to handle LOB columns. Option A is wrong because disabling LOB support would truncate LOB data. Option C is wrong because using a smaller LOB chunk size reduces memory per LOB but may not solve the memory issue; increasing instance size is more direct. Option D is wrong because using parallel tasks does not address memory constraints.
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.
✗
Set the LOB chunk size to 64 KB in the task settings.
Why it's wrong here
Smaller chunk size reduces memory per LOB but may not be sufficient; instance upgrade is more reliable.
✓
Increase the replication instance size to dms.c4.xlarge (8 GB RAM).
Why this is correct
More memory allows handling large LOB columns without running out of memory.
Related concept
Read the scenario before looking for a memorised answer.
✗
Split the 'Orders' table into multiple DMS tasks running in parallel.
Why it's wrong here
Parallel tasks do not reduce memory usage per task; each task still has memory constraints.
✗
Change the DMS task settings to disable LOB support for the 'Orders' table.
Why it's wrong here
Disabling LOB support would truncate LOB data, causing data loss.
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 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 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.
Deployment and Migration — This question tests Deployment and Migration — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Increase the replication instance size to dms.c4.xlarge (8 GB RAM). — Option B is correct because increasing the replication instance size provides more memory to handle LOB columns. Option A is wrong because disabling LOB support would truncate LOB data. Option C is wrong because using a smaller LOB chunk size reduces memory per LOB but may not solve the memory issue; increasing instance size is more direct. Option D is wrong because using parallel tasks does not address memory constraints.
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.
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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