System Design Thinking

system-design-thinking.md

System Design Thinking Guide

1. Clarify Requirements

• Understand the exact requirements of the system.
• Ask clarifying questions to make sure you know what the interviewer expects. For example, is the focus on scalability, availability, or fault tolerance?
• Determine functional and non-functional requirements (e.g., performance, security, reliability).

2. Estimate Scale

• Estimate the scale the system needs to handle (e.g., users per day, read/write operations per second, storage size).
• This helps you design a solution that fits the expected load and usage.

3. Define the Data Model

• Identify the key entities and relationships in your system.
• Define how the data will be structured (e.g., databases, tables, objects) and choose between SQL or NoSQL depending on the use case.

4. Design the High-Level Architecture

• Break down the system into core components (e.g., clients, APIs, databases, cache, load balancer, etc.).
• Define how components interact and the general flow of data through the system.
• Sketch a high-level architecture diagram.

5. Identify Key Design Challenges

• Discuss challenges like database scaling, consistency vs. availability, fault tolerance, and load balancing.
• Propose solutions for each challenge (e.g., replication, sharding, caching).

6. Optimize and Scale

• Discuss how the system can handle scale by introducing optimizations (e.g., caching, sharding, partitioning).
• Consider horizontal scaling (adding more machines) vs. vertical scaling (adding more resources to a machine).

7. Consider Trade-offs

• Highlight the trade-offs you are making (e.g., consistency vs. availability in the CAP theorem).
• Explain why you are making specific choices for the system’s performance and scalability.

8. Summarize the Design

• Recap the high-level architecture and key components.
• Summarize the challenges and solutions you proposed, as well as any improvements for future scaling.