AWS Certified SysOps Administrator – AssociateReliability and Business ContinuityMedium
A company operates a mission-critical web application on Amazon EC2 instances behind an Application Load Balancer (ALB). The application spans two Availability Zones. During peak traffic, the database (Amazon RDS for MySQL) becomes a bottleneck, leading to increased latency and failed transactions. The SysOps Administrator needs to improve the database's read performance and resilience without changing the application code. Which solution should be implemented?
- AMigrate the database to Amazon DynamoDB for better scalability.
- BEnable Multi-AZ deployment for the RDS instance.
- CCreate and configure RDS Read Replicas in different Availability Zones.
- DScale up the existing RDS instance to a larger instance type.
Show answer & explanationAnswer & explanation
Correct answer: C. Create and configure RDS Read Replicas in different Availability Zones.
RDS Read Replicas are specifically designed to offload read traffic from the primary database instance, improving read performance and increasing resilience by distributing the load. Placing them in different AZs further enhances availability. This requires no application code changes if the application is configured to use the read replica endpoints for read operations.
Why the other options are wrong
- A. Migrating to DynamoDB is a significant re-architecture that would require extensive application code changes, which the question seeks to avoid.
- B. Multi-AZ provides high availability for the primary instance (automatic failover) but does not improve read performance as it's a synchronous standby, not for read traffic offloading.
- D. Scaling up the primary instance might help with overall capacity but doesn't specifically address read bottlenecks as efficiently as read replicas, nor does it provide horizontal read scalability.
Amazon RDS Read Replicas
Asynchronous copies of a primary Amazon RDS database instance, used to offload read traffic, improve database availability, and serve as disaster recovery targets.
- Enhance read scalability and performance.
- Can be created within the same region or cross-region.
- Do not automatically fail over to become the primary instance.
- Requires application to direct read queries to the replica endpoint.
Memory trick: Reads are slow? Replicas help them grow!