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Difficulty: MediumPerformance and Scalability Optimization

A corporate payroll provider is launching a self-service year-end tax document portal. On the day tax forms are released, the portal expects an immediate traffic spike from 100100 requests per second to 120000120{}000 requests per second. The application consists of a read-heavy reporting dashboard hosted on an Auto Scaling Group of Amazon EC2 instances behind an Application Load Balancer (ALB). The dashboard queries an Amazon RDS for PostgreSQL database in a Multi-AZ deployment. Which two actions should the solutions architect recommend to optimize performance and scalability during this spike?

  1. Contact AWS Support to pre-warm the Application Load Balancer to the expected traffic rate of 120000120{}000 requests per second.Answer
  2. Create Amazon RDS read replicas and configure the application to send read-heavy dashboard queries to the read replica endpoints.Answer
  3. C
    Direct reporting dashboard queries to the standby DB instance endpoint in the secondary Availability Zone of the RDS Multi-AZ deployment.
  4. D
    Rely on the default automatic scaling of the Application Load Balancer to handle the spike and configure target tracking scaling policies.
  5. E
    Configure the EC2 Auto Scaling Group with a 1515-second cooldown period to trigger rapid scale-out events as traffic begins to spike.

Answer

Contact AWS Support to pre-warm the Application Load Balancer to the expected traffic rate, and create Amazon RDS read replicas to handle the read-heavy dashboard queries.
To handle a sudden, massive traffic spike (from 100100 to 120000120{}000 requests per second), the Application Load Balancer must be pre-warmed by AWS Support because its automatic scaling cannot react instantly. To handle the read-heavy load on the database layer, RDS read replicas must be used since the secondary standby DB instance in a Multi-AZ deployment is passive and cannot serve read traffic.

Step-by-Step Solution

1
Analyze the load balancer scaling behavior during a sudden 1200×1200\times traffic spike.
The Application Load Balancer cannot scale its capacity quickly enough, causing dropped connections and service timeouts.
ALB auto-scaling is designed to handle gradual increases in traffic, not instantaneous spikes of this magnitude.
2
Address the load balancer scaling limitation.
Submit a support ticket to pre-warm the Application Load Balancer to the expected 120000120{}000 requests per second.
Pre-warming ensures the load balancer has sufficient capacity provisioned before the traffic spike begins.
3
Evaluate read query scaling on the database layer.
Deploy RDS read replicas to offload read-heavy traffic from the primary DB instance.
The standby instance in an RDS Multi-AZ deployment is passive and cannot process read queries, making read replicas necessary for read scaling.
4
Assess the Auto Scaling Group cooldown configuration.
Avoid reducing the cooldown period below the instance launch and bootstrapping time.
A cooldown period that is too short causes the Auto Scaling group to launch unnecessary instances continuously before the previously launched instances can register as healthy.

Key Concept

Handling sudden flash traffic spikes requires pre-warming the load balancing layer and utilizing read replicas to scale read-heavy database workloads.
Estimated Time:2m 0s
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Topics

Performance and Scalability Optimization

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