SNAKE - System Design Principles to crack a system design in 5 steps

System design questions can be daunting, but with a structured approach, you can tackle them confidently. Here are five steps to help you systematically address any system design question:

1. Scenario: Understanding the Case and Interface

• Typical Use Cases: Identify the primary use cases your system needs to support. Understand the end-user requirements and the core functionalities the system should provide.
• Abstraction: Determine the level of abstraction your system should offer. This involves defining the system boundaries and the high-level components.
• APIs: Design the APIs that will facilitate communication between different components of your system. Consider the inputs, outputs, and actions for each API endpoint.

2. Necessary: Constraints and Hypotheses

• Total Users and Daily Active Users: Estimate the number of users your system will serve and the daily active user count. This helps in understanding the scale.
• Transactions: Determine the number of transactions your system needs to handle. This includes read and write operations.
• Concurrency: Assess the number of concurrent users or parallel executions your system must support.
• Peak Load: Identify the peak load your system is expected to handle. This includes traffic spikes and maximum transaction rates.
• Performance Requirements: Define the acceptable latency and response time. Understand how fast your system needs to be and the maximum delay it can tolerate.

3. Application: Services and Algorithms

• Service Design: Break down your system into individual services or modules. Define the responsibilities and interactions of each service.
• Algorithm Complexity: Perform a complexity analysis of the core algorithms. Understand the time and space complexity (Big O notation) to ensure efficiency.

4. Kilobit: Data Considerations

• Data Generation: Estimate the amount of data generated by your system. This includes user-generated content, logs, and metadata.
• Storage Requirements: Determine the storage space needed to persist the data. Plan for future growth.
• Data Storage Solutions: Decide where to store the data. Choose between file systems, SQL databases, NoSQL databases, or a combination based on your requirements.

5. Evolve: Optimization and Scalability

• Optimization: Identify areas for performance improvement. Optimize your system for speed, memory usage, and resource efficiency.
• Extensibility: Ensure your system can be extended with new features and components without significant rework.
• Scalability: Design your system to scale horizontally and vertically. Plan for adding more servers, instances, and resources as demand grows.
• Availability: Ensure high availability of your system through redundancy, failover mechanisms, and disaster recovery plans.

4S Analysis Framework

Alternatively, you can use the 4S Analysis framework to structure your approach:

Scenario

• Ask: Clarify the problem statement and requirements.
• Features: Identify the core features your system needs to support.
• QPS (Queries Per Second): Determine the expected query rate.
• DAU (Daily Active Users): Estimate the daily active user count.
• Interfaces: Define the interfaces for user interaction and system integration.

Service

• Split: Break down the system into smaller, manageable services or modules.
• Application: Design the core application logic and service responsibilities.
• Module: Define the individual modules and their interactions.

Storage

• Schema: Design the database schema to support your data model.
• Data: Plan for data storage, indexing, and retrieval.
• SQL/NoSQL/File System: Choose the appropriate storage solutions based on your data needs.

Scale

• Sharding: Implement sharding for distributed data storage and retrieval.
• Optimize: Optimize your system for performance and efficiency.
• Special Case: Address special cases and edge scenarios to ensure robustness.

By following these steps and frameworks, you can systematically and confidently approach any system design question, ensuring a comprehensive and efficient solution.