DBS-C01 Monitoring and Troubleshooting Practice Question
A company is migrating an on-premises Oracle database to Amazon Aurora PostgreSQL. The migration uses AWS Database Migration Service (DMS) with ongoing replication. The team notices that the target Aurora database is falling behind the source during peak hours. Which of the following actions would MOST effectively improve the replication performance?
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
✓
Configure the DMS task to use 'Limited LOB mode' and increase the max LOB size
The most effective action. Using 'Limited LOB mode' in AWS DMS reduces the overhead of replicating large objects by only transferring metadata until the LOB is accessed, and increasing the max LOB size ensures that LOBs fit within a single transaction, preventing fragmentation. Option A is incorrect because disabling Multi-AZ does not directly affect DMS replication performance; Multi-AZ provides high availability but does not impact replication throughput. Option B, increasing the Aurora instance size, may help if the instance is CPU or memory constrained, but the primary bottleneck in replication is often the handling of large objects, making DMS task configuration more targeted. Option C is incorrect because using a smaller instance would worsen performance, not improve it.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Disable Multi-AZ on the target Aurora cluster
Why it's wrong here
Disabling Multi-AZ does not improve replication performance; it only removes high availability, so this is incorrect.
- ✗
Increase the Amazon Aurora instance size
Why it's wrong here
Increasing the instance size may help if resources are constrained, but it is not the most effective solution; the bottleneck is likely large object handling, which DMS configuration addresses more directly.
- ✗
Use a smaller Aurora instance to reduce write latency
Why it's wrong here
Using a smaller instance would reduce performance, not improve it, so this is incorrect.
- ✓
Configure the DMS task to use 'Limited LOB mode' and increase the max LOB size
Why this is correct
Configuring 'Limited LOB mode' and increasing max LOB size reduces overhead for large objects and improves replication efficiency, making this the most effective action.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.