The answer is to reduce the number of tables being migrated in the task and to increase the replication instance class. This resolves the DMS insufficient memory error because the replication instance’s memory is exhausted when handling large transaction caches, complex transformation rules, or high-volume data loads from a 3 TB source. By reducing the table count, you lower the concurrent memory demand for caching and LOB handling, while scaling the instance class (e.g., from dms.c5.large to dms.c5.2xlarge) directly adds RAM and CPU to accommodate the workload. On the AWS Certified Database Specialty DBS-C01 exam, this scenario tests your understanding of DMS resource sizing and the common trap of assuming only instance scaling is needed—often, task segmentation is equally critical. A key memory tip is “Tables trim, instance brim”: if memory is thin, trim the table count and brim the instance size.
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 3 TB on-premises Oracle database to Amazon Aurora PostgreSQL using AWS DMS. The migration task is failing with an error indicating insufficient memory. Which TWO actions should the company take to resolve this issue? (Choose TWO.)
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Increase the instance class of the DMS replication instance.
Option C is correct because the 'insufficient memory' error during an AWS DMS migration indicates that the replication instance lacks the memory required to handle the data volume, transformation rules, or cache for large transactions. Increasing the instance class (e.g., from dms.c5.large to dms.c5.2xlarge) provides more memory and CPU, directly resolving the resource constraint.
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.
✗
Change the target database engine to Amazon RDS for MySQL.
Why it's wrong here
Changing the target engine does not resolve the memory issue.
✗
Disable Multi-AZ on the DMS replication instance.
Why it's wrong here
Multi-AZ does not affect memory; it provides high availability.
✓
Increase the instance class of the DMS replication instance.
Why this is correct
A larger instance class provides more memory to handle the migration.
Related concept
Read the scenario before looking for a memorised answer.
✓
Reduce the number of tables being migrated in the task.
Read the scenario before looking for a memorised answer.
✗
Use a smaller instance class for the DMS replication instance.
Why it's wrong here
A smaller instance class would have less memory, worsening the issue.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates might confuse a DMS replication instance memory issue with a target database performance issue, leading them to incorrectly change the target engine or disable Multi-AZ instead of scaling the replication instance.
Detailed technical explanation
How to think about this question
AWS DMS replication instances use memory for caching table data, handling LOBs, and running transformation rules; the default memory allocation for tasks is 60% of the instance's total memory, with the rest reserved for OS and DMS processes. For large migrations (e.g., 3 TB), the instance must also handle full-load caching and ongoing replication change cache, which can exceed available memory if the instance class is undersized. The error often occurs when the task's 'MaxFullLoadSubTasks' or 'ParallelLoadThreads' settings are too high for the instance's memory, but increasing the instance class is the primary fix.
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.
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 instance class of the DMS replication instance. — Option C is correct because the 'insufficient memory' error during an AWS DMS migration indicates that the replication instance lacks the memory required to handle the data volume, transformation rules, or cache for large transactions. Increasing the instance class (e.g., from dms.c5.large to dms.c5.2xlarge) provides more memory and CPU, directly resolving the resource constraint.
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.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
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
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.