Tech-Notes

System Design

a systematic approach to building and engineering systems

• process of defining the architecture, interfaces, and data for a system that satisfies specific requirements

High-Level Design (HLD) vs. Low-Level Design (LLD)

are two phases and each focusing on different levels of system design.

Key Differences Between HLD and LLD

Aspect	High-Level Design (HLD)	Low-Level Design (LLD)
Focus	System architecture, major components	Component internals, detailed logic
Audience	Architects, project managers, senior devs	Developers
Details	Modules, data flow, database architecture	Class structure, data structures, API details, DB fields
Example	explain dataflow b/w each services in MS	explain particular service in MS

System design Examples

1. URL Shortners

Scaling:

(https://www.youtube.com/watch?v=Nx4bvwU0DqE)[https://www.youtube.com/watch?v=Nx4bvwU0DqE]

| Horizontal scaling | Vertical scaling | |—————————|———————————–| | More number of servers | Bigger server | | LoadBalancing required | N/a | | Resilient | Single point of failure | | Network calls(Rpc) | Inter process communication | | Data inconsistence | Consistence | | Scales well as user grow | Hardware limit | —————————————————————–

Load Balancing

Types of distribution

1. Random
2. Round Robin
3. Random(weight for ram and cpu cycles)

categories of load balancing

1. stateless - round robin
2. statefull - least connections

Important points to consider when system design:

1. Scalability
2. Performance
3. Reliability/Availability
4. Security
5. Maintainability: documentation and well-organized code.
6. Interoperability: work seamlessly with other systems
7. Usability: clear user interface.
8. Cost-effectiveness

CDN

Content delivery network

• static pages, images, files, videos will be served from cdn

Logging & Monitoring

Observability