The answer is a DB subnet group with subnets in at least two Availability Zones. This configuration is essential because Amazon RDS Multi-AZ deployment automatically provisions and maintains a synchronous standby replica in a different AZ, enabling automatic failover with minimal downtime during an AZ outage. On the AWS Certified Data Engineer Associate DEA-C01 exam, this concept tests your understanding of high availability architecture for managed databases, often appearing as a scenario where you must distinguish between Multi-AZ for failover and Read Replicas for read scaling. A common trap is confusing Multi-AZ with a single-AZ setup that uses manual snapshots—remember that automatic failover requires the standby to be in a separate AZ, not just any secondary instance. Memory tip: think “Multi-AZ = Mirror in Another Zone” for automatic failover.
DEA-C01 Data Store Management Practice Question
This DEA-C01 practice question tests your understanding of data store management. 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 data engineer is setting up an Amazon RDS for MySQL database. The database must be highly available and automatically failover in case of an AZ outage. Which TWO configurations should the engineer enable? (Choose TWO.)
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Multi-AZ deployment
Multi-AZ deployment (Option A) automatically provisions and maintains a synchronous standby replica in a different Availability Zone (AZ). In the event of an AZ outage, Amazon RDS automatically fails over to the standby, ensuring high availability with minimal downtime. This is the core mechanism for automatic failover in RDS for MySQL.
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.
✓
Multi-AZ deployment
Why this is correct
Multi-AZ creates a standby instance in a different Availability Zone for automatic failover.
Related concept
Read the scenario before looking for a memorised answer.
✓
A DB subnet group with subnets in at least two Availability Zones
Why this is correct
A Multi-AZ deployment requires subnets in at least two AZs to place the primary and standby.
Related concept
Read the scenario before looking for a memorised answer.
✗
Enhanced Monitoring
Why it's wrong here
Enhanced Monitoring provides metrics, not high availability.
✗
Automated backups with a retention period of 30 days
Why it's wrong here
Backups are for recovery, not for failover.
✗
Read replicas in a different Region
Why it's wrong here
Read replicas do not provide automatic failover; they are for read scaling.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse read replicas or automated backups with high availability failover, but only Multi-AZ deployment provides automatic, synchronous failover within the same region.
Detailed technical explanation
How to think about this question
In a Multi-AZ deployment, the standby replica is kept in sync using synchronous replication to the primary DB instance. During failover, RDS automatically updates the DNS record to point to the standby, which typically completes within 60-120 seconds. The DB subnet group (Option B) must include subnets in at least two AZs to allow RDS to place the primary and standby in different AZs, making it a required supporting configuration for Multi-AZ.
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
An e-commerce site experiences heavy traffic on Black Friday and near-zero traffic during off-peak weeks. Rather than provisioning permanent large VMs, the team uses auto-scaling groups that add capacity automatically under load and reduce it overnight. Questions like this test whether you understand elasticity, availability zones, and cloud compute scaling patterns.
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.
Data Store Management — This question tests Data Store Management — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Multi-AZ deployment — Multi-AZ deployment (Option A) automatically provisions and maintains a synchronous standby replica in a different Availability Zone (AZ). In the event of an AZ outage, Amazon RDS automatically fails over to the standby, ensuring high availability with minimal downtime. This is the core mechanism for automatic failover in RDS for MySQL.
What should I do if I get this DEA-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.
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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.
Question Discussion
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