System Design Process

Step 1: Outline use cases, constraints, and assumptions

• Gather requirements and scope the problem.
• Clarify the use cases, system's constraints
• Discuss about your assumptions

Questions to Ask

• Who is going to use it?
• How are they going to use it?
• How many users are there?
• What does the system do?
• What are the inputs and outputs of the system?
• How much data do we expect to handle?
• How many requests per second do we expect?
• What is the expected read to write ratio?

Step 2: Create a high level design

Outline a high level design with all important components.

• Walk through your system from end-to-end
• Sketch a high-level abstract design.
• The goal of this is to outline all the important components that your architecture will need.

Step 3: Design core components

Dive into details for each core component.

Step 4: Scale the design

Identify and address bottlenecks, given the constraints. For example, do you need the following to address scalability issues?

• Load balancer
• Horizontal scaling
• Caching
• Database sharding