SAA-C03 Question 248
Select 2A company is running a web application on an Amazon EC2 instance that connects to an Amazon RDS database. The application requires high availability and disaster recovery. The company wants to ensure that their web application and database remain operational in the event of an entire AWS Region outage. Which solution should you recommend?
- A
Deploy the EC2 instance and RDS database in a single Availability Zone and enable RDS Multi-AZ.
- B
Use an EC2 Auto Scaling group across multiple Regions and create a read replica of the RDS database in the secondary Region.
- C
Deploy the EC2 instance in multiple Availability Zones and enable RDS Multi-AZ.
- D
Set up a backup EC2 instance and a cross-region read replica of the RDS database in a secondary Region.
- E
Use AWS Elastic Load Balancing to distribute traffic across EC2 instances in multiple Regions and implement RDS Global Database.
Show answer and explanation
Correct answers: D, E
Explanation
To ensure high availability and disaster recovery in the event of a Regional outage, you need to deploy resources in multiple AWS Regions. Setting up a backup EC2 instance in the secondary Region and creating a cross-region read replica for the RDS database provides a disaster recovery solution. Additionally, using AWS Elastic Load Balancing for EC2 in multiple Regions and RDS Global Database ensures automated failover and minimal downtime, making these options the best solution for the given scenario.
- A. Incorrect.
Deploying resources in a single Availability Zone (AZ) does not provide protection against Regional outages, even with Multi-AZ enabled for RDS. This approach is not suitable for ensuring high availability in the event of a Regional failure.
- B. Incorrect.
While an Auto Scaling group across multiple Regions can provide availability for EC2 instances, creating only a read replica of the RDS database in the secondary Region does not provide full disaster recovery capabilities because read replicas are not writable until they are promoted, which requires manual intervention.
- C. Incorrect.
Deploying the EC2 instance in multiple AZs and enabling RDS Multi-AZ provides high availability within a single Region, but it does not protect against a complete Regional outage.
- D. Correct.
Setting up a backup EC2 instance and a cross-region read replica of the RDS database ensures disaster recovery in case of a Regional outage. The read replica can be promoted to a primary database in the secondary Region, and the backup EC2 instance can be launched to replace the failed primary instance.
- E. Correct.
Using AWS Elastic Load Balancing to distribute traffic across EC2 instances in multiple Regions ensures high availability for the web application. Implementing RDS Global Database provides a highly available and disaster-tolerant database solution with replication across Regions.