SAA-C03 Design Resilient Architectures Practice Question
A company runs a critical application on Amazon EC2 instances in a single Availability Zone. The application writes data to an Amazon RDS for MySQL DB instance that is not Multi-AZ. The company wants to improve the resilience of the database tier so that it can survive an Availability Zone failure with minimal downtime and no data loss. The application uses the database endpoint from the RDS console. Which solution meets these requirements?
⚠ Common exam trap
Candidates often confuse read replicas with Multi-AZ standbys. Read replicas are for offloading reads and can be promoted manually, but they use asynchronous replication and do not provide 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
✓
Convert the DB instance to a Multi-AZ deployment and update the application to use the same endpoint.
Multi-AZ deployments for Amazon RDS provide a synchronous standby replica in a different Availability Zone. In the event of an AZ failure, RDS automatically fails over to the standby, and the application continues to use the same endpoint. Because replication is synchronous, there is no data loss. This meets the requirements of minimal downtime and no data loss without application changes.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Create a read replica in another Availability Zone and manually promote it if the primary fails.
Why it's wrong here
A read replica uses asynchronous replication, so it may lag behind the primary. In a failure, some data may be lost. Manual promotion also requires intervention, leading to longer downtime. This does not meet the no data loss and minimal downtime requirements.
- ✓
Convert the DB instance to a Multi-AZ deployment and update the application to use the same endpoint.
Why this is correct
Converting to Multi-AZ creates a synchronous standby in a different AZ. RDS automatically fails over to the standby in the event of an AZ failure, and the application can continue using the same endpoint. This provides minimal downtime and no data loss because replication is synchronous.
- ✗
Enable automated backups with a retention period of 35 days and copy the backups to another Region.
Why it's wrong here
Automated backups and cross-Region copy improve durability and disaster recovery, but they do not provide automatic failover. In an AZ failure, the DB instance would be unavailable until restored, causing significant downtime and potential data loss since the last backup. This does not meet the minimal downtime and no data loss requirements.
- ✗
Migrate the database to Amazon DynamoDB with global tables and update the application to use the DynamoDB endpoint.
Why it's wrong here
Migrating to DynamoDB requires significant application changes and is not a like-for-like replacement for a relational database. Global tables provide multi-Region replication but do not automatically fail over within a Region. This introduces complexity and does not guarantee no data loss without proper configuration.
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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 SAA-C03 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 SAA-C03 exam.