System Design Strategy

1. Determine Functional Requirements

• What am I making

• Where is the code supposed to be implemented

• Are there multiple instances of the service

• Are there any weird edge cases

2. Determine Non-Functional Requirements

Scalability

• Throughput - how many requests are received per second
  • Horizontal vs Vertical scaling

• Storage capacity - how much IO, read and write

Performance

• Availability - number of successful requests / total number of requests
  • Fail-Open vs Fail-Closed (Consider what features would need to Fail-Closed)

• Latency - how long does it take to make a single request

3. Design it

Determine Storage

• In memory store
  • Redis - use when required fast, and not storing alot

Determine Severs

• New service
  • Good when feature is required across multiple services

• Add to existing service
  • Good when feature only required for a single service

Algorithm