DBS-C01 Management and Operations Practice Question
A company uses Amazon RDS for MySQL with Multi-AZ deployment. The primary instance fails and the database administrator notices that the failover did not happen automatically. What is the MOST likely cause?
⚠ Common exam trap
A common mix-up: candidates confuse read replicas with Multi-AZ standby instances, assuming a read replica can automatically take over during a failure, when in fact only a Multi-AZ standby provides automatic failover.
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 DB instance is configured as a read replica.
A read replica in Amazon RDS for MySQL is a separate DB instance that asynchronously replicates from a source instance. It does not support automatic failover; if the source instance fails, the read replica remains a standalone read-only instance and does not become the primary. Multi-AZ failover only occurs between a primary and its standby in the same region, not to a read replica.
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 DB instance is in a public subnet.
Why it's wrong here
Public subnet does not affect Multi-AZ failover.
- ✗
Enhanced Monitoring is disabled.
Why it's wrong here
Enhanced Monitoring provides metrics, not failover.
- ✗
The standby instance is in a different VPC.
Why it's wrong here
Multi-AZ requires same VPC.
- ✓
The DB instance is configured as a read replica.
Why this is correct
Read replicas do not have automatic failover.
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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.