SAP-C02 Question 472
Single answerA financial services company runs a critical trading application on AWS. The application consists of an Auto Scaling group of EC2 instances behind an Application Load Balancer in two Availability Zones. Recently, one of the Availability Zones experienced an outage, causing degraded performance for the application. As a Solutions Architect, you are tasked with improving the application's reliability. Which strategy should you implement?
- A
Increase the number of instances in the Auto Scaling group to handle more traffic during outages.
- B
Add a third Availability Zone to the existing Auto Scaling group and configure the load balancer to distribute traffic across all three.
- C
Switch to a single Availability Zone with a larger instance size to handle peak traffic.
- D
Enable EC2 instance recovery to automatically recover failed instances in the affected Availability Zone.
Show answer and explanation
Correct answer: B
Explanation
The best strategy to improve reliability is to add a third Availability Zone to the existing architecture. This ensures that the application can continue to operate with minimal impact even if one Availability Zone becomes unavailable. Distributing traffic across three Availability Zones using the load balancer enhances fault tolerance and reliability.
- A. Incorrect.
Increasing the number of instances in the Auto Scaling group does not directly address the reliability issue caused by a single Availability Zone outage. Traffic distribution across multiple zones is critical for improving reliability.
- B. Correct.
Adding a third Availability Zone improves reliability by reducing the impact of an Availability Zone outage. The load balancer can distribute traffic across all three zones, ensuring higher availability.
- C. Incorrect.
Switching to a single Availability Zone introduces a single point of failure, which reduces reliability. Multi-AZ designs are recommended for high availability.
- D. Incorrect.
Enabling EC2 instance recovery helps recover failed instances but does not mitigate the impact of an entire Availability Zone outage. This feature focuses on individual instance recovery, not zonal reliability.