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Difficulty: MediumPerformance and Scalability Optimization

A financial technology company is launching a new mobile app that provides real-time portfolio valuation updates to users. The application backend is deployed on Amazon EC2 instances inside an Auto Scaling group, fronted by an Application Load Balancer (ALB). The application queries an Amazon RDS for MySQL Multi-AZ database. The company expects the traffic to spike from 1,0001,000 requests per second to over 500,000500,000 requests per second within 55 minutes at the market open every day. Users require near-instantaneous responses, and session state must be persisted across multiple Availability Zones to prevent data loss if an instance fails. Which combination of actions will ensure the application scales efficiently and maintains low latency during the morning traffic spikes?

  1. Request AWS Support to pre-warm the Application Load Balancer prior to the daily market open, deploy Amazon ElastiCache for Redis to store session state with replication, and configure RDS Read Replicas to offload read traffic from the primary database instance.Answer
  2. B
    Request AWS Support to pre-warm the Application Load Balancer prior to the daily market open, deploy Amazon ElastiCache for Memcached with multi-AZ replication to manage session persistence, and configure RDS Read Replicas to offload read traffic from the primary database instance.
  3. C
    Depend on the Application Load Balancer's native scaling to handle the traffic spike, deploy Amazon ElastiCache for Redis to cache session states, and configure the application to route read queries to the standby database instance in the Multi-AZ deployment during peak hours.
  4. D
    Request AWS Support to pre-warm the Application Load Balancer prior to the daily market open, deploy Amazon ElastiCache for Redis to store session state with replication, and configure the EC2 Auto Scaling group with a cooldown period of 15 seconds to ensure new instances are added rapidly during the spike.

Answer

Request AWS Support to pre-warm the Application Load Balancer prior to the daily market open, deploy Amazon ElastiCache for Redis to store session state with replication, and configure RDS Read Replicas to offload read traffic from the primary database instance.
The correct answer combines three standard scalability techniques: pre-warming the ALB to handle the massive 500,000 requests per second traffic spike immediately; using ElastiCache for Redis to store session state with multi-AZ replication; and offloading read operations to RDS Read Replicas to avoid overloading the primary database instance.

Step-by-Step Solution

1
Address the rapid, massive traffic spike at the Application Load Balancer tier.
Contact AWS Support to pre-warm the Application Load Balancer.
An Application Load Balancer scales automatically, but a sudden spike from 1,000 to 500,000 requests per second in 5 minutes exceeds its default scaling speed, leading to connection timeouts. Pre-warming prepares the ALB resources in advance.
2
Address the session persistence and replication requirements.
Deploy an Amazon ElastiCache for Redis cluster with replication.
Redis is designed to handle key-value data with replication and durability, ensuring session data persists across Availability Zones. Memcached does not natively support multi-AZ replication.
3
Address the database read scalability.
Deploy RDS Read Replicas and point the application's read queries to them.
RDS Read Replicas offload the read traffic from the primary DB instance, which preserves write capacity and resolves high CPU utilization. Multi-AZ standby instances are passive and cannot accept read queries.

Key Concept

Designing for high-performance and rapid scalability across compute, load balancing, caching, and database layers.
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Topics

Performance and Scalability Optimization

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