DEA-C01 Data Operations and Support Practice Question
A data engineer is using AWS Database Migration Service (AWS DMS) to replicate ongoing changes from an Amazon RDS for MySQL database to an Amazon S3 bucket in Parquet format. The replication task is configured with full load plus change data capture (CDC). After several hours, the engineer notices that the S3 bucket contains only the full load data and no incremental changes. Which action should the engineer take to ensure CDC changes are captured?
⚠ Common exam trap
The trap here is assuming that CDC will work automatically once the DMS task is set to full load plus CDC, without verifying source database prerequisites like binary logging.
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
✓
Enable binary logging on the source RDS for MySQL instance and set the binlog_format parameter to ROW.
For AWS DMS to perform ongoing replication from MySQL, the source must have binary logging enabled and binlog_format set to ROW. Without these settings, DMS cannot read the transaction log to capture changes. The engineer must enable binary logging and set the format to ROW, then restart the task. Other actions like scaling the instance or enabling Multi-AZ do not enable CDC.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Increase the DMS replication instance size to handle the change volume.
Why it's wrong here
Scaling the replication instance may improve performance, but it does not enable CDC if the source database is not configured to provide change data. The absence of incremental changes indicates a configuration issue with binary logging, not insufficient resources. A larger instance will still only perform the full load if CDC prerequisites are missing.
- ✗
Enable Multi-AZ on the source RDS for MySQL instance.
Why it's wrong here
Multi-AZ provides high availability by maintaining a standby replica, but it does not affect binary logging or CDC capture. DMS reads from the primary instance, and Multi-AZ does not change the binlog settings. Enabling Multi-AZ would not cause incremental changes to appear in S3; it is unrelated to the CDC configuration.
- ✗
Modify the DMS task to use a different target endpoint for CDC data.
Why it's wrong here
The target endpoint is already S3, and the task is configured for full load plus CDC. Changing the target endpoint would not address the root cause, which is likely the source database's binary logging configuration. DMS can write CDC data to S3; the issue is that no CDC data is being generated or read from the source.
- ✓
Enable binary logging on the source RDS for MySQL instance and set the binlog_format parameter to ROW.
Why this is correct
AWS DMS requires binary logging enabled on the source MySQL instance for CDC, and the binlog format must be ROW to capture row-level changes. Without this, DMS cannot read the transaction log and will only perform the initial full load. Setting binlog_format to ROW is a prerequisite for ongoing replication, so this action directly enables CDC.
Quick reference
AWS S3 Storage Class Comparison
| Storage Class | Min Duration | Retrieval | Use Case |
|---|---|---|---|
| S3 Standard | None | Immediate | Frequently accessed data |
| S3 Standard-IA | 30 days | Immediate | Infrequent access, rapid retrieval |
| S3 One Zone-IA | 30 days | Immediate | Non-critical infrequent data |
| S3 Intelligent-Tiering | None | Immediate–hours | Unknown or changing access patterns |
| S3 Glacier Instant | 90 days | Milliseconds | Archive with instant retrieval |
| S3 Glacier Flexible | 90 days | Minutes–hours | Archive, flexible retrieval |
| S3 Glacier Deep Archive | 180 days | Hours | Long-term compliance archive |
Go deeper
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Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Amazon Web Services exam blueprint
This DEA-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 DEA-C01 exam.