System Design – Part 1: Intro

What’s system design?

The process of defining the architecture, components, modules, interfaces and data for a system to satisfy specified requirements.

If we break down the design process, you can see the flow is like below:

What’s good design?

1. Healthiness
   • Execution: Every component works fine without issue
   • Communication: Communication between components are smooth and low latency
2. Simplicity
   • No more; no less
   • Understandable

Funamental questions in system design

1. Please design a specific system
2. Please evaluate query per second (QPS)
3. Please scale the system

How to crack a design?

We can follow SNAKE principle

• Scenario: case/interface

We need to break down the system and list out the core features that we need to deal with.

• Necessary: constrain/hypothesis

We need to know what daily active user (DAU), query per second (QPS), transaction per second (TPS) and peak usage etc. we target for.

• Application: service/algorithm

We need to design what service or algorithm we’re going to implement.

• Kilobit: data

How will we store data and provide data to users?

• Evolve

Check if there is any new constrains, or use cases or performance issue etc.