- A
The DB instance is in a public subnet.
Why wrong: Public subnet does not affect Multi-AZ failover.
- B
Enhanced Monitoring is disabled.
Why wrong: Enhanced Monitoring provides metrics, not failover.
- C
The standby instance is in a different VPC.
Why wrong: Multi-AZ requires same VPC.
- D
The DB instance is configured as a read replica.
Read replicas do not have automatic failover.
Question 1,139 of 1,730
Read Replicas vs Multi-AZ: Failover Differences
This DBS-C01 practice question tests your understanding of management and operations. 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 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?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"most likely"Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Clue:
"primary"Why it matters: Asks for the main purpose or function, not a secondary benefit. Eliminate answers that describe side-effects or partial functions.
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.
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.
- ✗
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.
Clue confirmation
The clue words "most likely", "primary" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that 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.
Detailed technical explanation
How to think about this question
Multi-AZ failover relies on synchronous replication between the primary and standby, with the standby having a pre-warmed buffer cache and a separate DNS CNAME that is updated to point to the standby upon failure. Read replicas use asynchronous replication (binlog-based) and are not part of the Multi-AZ failover mechanism; they must be manually promoted to become writable, which changes the endpoint and does not preserve the original primary's DNS name.
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 healthcare organisation deploys an application with a public-facing web tier and a private database tier. The database subnet has no public IP and only accepts connections from the web tier's security group. Questions like this test whether you can design cloud network isolation using VNets/VPCs, subnets, and security group rules.
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.
- →
Management and Operations — study guide chapter
Learn the concepts, then practise the questions
- →
Management and Operations practice questions
Targeted practice on this topic area only
- →
All DBS-C01 questions
1,730 questions across all exam domains
- →
AWS Certified Database Specialty DBS-C01 study guide
Full concept coverage aligned to exam objectives
- →
DBS-C01 practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Related DBS-C01 practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Workload-Specific Database Design practice questions
Practise DBS-C01 questions linked to Workload-Specific Database Design.
Deployment and Migration practice questions
Practise DBS-C01 questions linked to Deployment and Migration.
Management and Operations practice questions
Practise DBS-C01 questions linked to Management and Operations.
Monitoring and Troubleshooting practice questions
Practise DBS-C01 questions linked to Monitoring and Troubleshooting.
Database Security practice questions
Practise DBS-C01 questions linked to Database Security.
DBS-C01 fundamentals practice questions
Practise DBS-C01 questions linked to DBS-C01 fundamentals.
DBS-C01 scenario practice questions
Practise DBS-C01 questions linked to DBS-C01 scenario.
DBS-C01 troubleshooting practice questions
Practise DBS-C01 questions linked to DBS-C01 troubleshooting.
Practice this exam
Start a free DBS-C01 practice session
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Questions learners often ask
What does this DBS-C01 question test?
Management and Operations — This question tests Management and Operations — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: 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.
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.
Are there clue words in this question I should notice?
Yes — watch for: "most likely", "primary". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
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 →
Keep practising
More DBS-C01 practice questions
- A company is deploying a new application on Amazon RDS for PostgreSQL. The security policy requires that all data be enc…
- Match each AWS service to its primary purpose.
- A financial services company runs a production Amazon Aurora MySQL database cluster (1 writer, 2 readers) in us-east-1.…
- A company is designing a database for a global e-commerce platform that requires low-latency reads and writes from multi…
- A security auditor reviews the output of a DynamoDB table description command as shown in the exhibit. Which statement a…
- A company is migrating an on-premises Oracle database to Amazon RDS for Oracle. The database contains sensitive data tha…
Last reviewed: Jul 4, 2026
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.