System-Design by The Webspace

Basics of System Design

What is System Design?

• System design refers to the process of defining the architecture, components, modules, interfaces, and data of a system to satisfy specified requirements.

---

Requirements Gathering Process

1. Understand the Problem: Identify the scope and objectives.
2. Stakeholder Involvement: Gather input from stakeholders.
3. Document Requirements: Clearly define functional and non-functional requirements.
4. Prioritize Requirements: Determine critical features for MVP.

---

Functional vs Non-Functional Requirements

• Functional Requirements: Define specific behavior or functions (e.g., login, data retrieval).
• Non-Functional Requirements: Define system attributes like performance, scalability, and security.

---

Components of System Design

• Frontend: User interfaces and experience.
• Backend: Servers, APIs, and databases.
• Database: Storage and retrieval of data.
• Networking: Communication between components.

---

System Design Life Cycle | SDLC (Design)

1. Requirements Analysis
2. System Architecture
3. Component Design
4. Implementation
5. Testing
6. Deployment
7. Maintenance

---

Scalability in System Design

• The ability of a system to handle growth in workload efficiently.

Scalability and How to Achieve It

• Horizontal Scaling: Adding more machines.
• Vertical Scaling: Upgrading existing machines.

Horizontal vs Vertical Scaling

Feature	Horizontal Scaling	Vertical Scaling
Cost	Higher	Lower
Implementation	Complex	Simpler
Scalability Limit	High	Limited

---

Primary Bottlenecks that Hurt Scalability

• Database Overload
• Network Latency
• CPU and Memory Constraints

---

System Architectural Styles

Monolithic Architecture

• Single codebase.
• Pros: Simple to develop.
• Cons: Difficult to scale and maintain.

Microservices Architecture

• Modular services.
• Pros: Scalable and maintainable.
• Cons: Complex to implement.

Monolithic vs Microservices Architecture

Feature	Monolithic	Microservices
Scalability	Limited	High
Flexibility	Low	High

Event-Driven Architecture

• Systems respond to events asynchronously.

Serverless Architecture

• Pay-as-you-go execution model.

---

High-Level Design (HLD)

What is High-Level Design?

• Focuses on the architecture and major components of a system.

---

Availability in System Design

• Ensures the system is operational and accessible.

Consistency in System Design

• Guarantees data integrity across the system.

Reliability in System Design

• Ensures the system operates correctly and recovers from failures.

CAP Theorem

• Consistency: Every read receives the latest write.
• Availability: Every request receives a response.
• Partition Tolerance: System functions despite network failures.

---

Difference Between Concurrency and Parallelism

• Concurrency: Multiple tasks make progress simultaneously.
• Parallelism: Tasks execute simultaneously on different processors.

---

Load Balancer

• Distributes traffic across servers to improve performance and reliability.

Consistent Hashing

• Distributes data across nodes to ensure minimal redistribution during changes.

Content Delivery Network (CDN)

• Caches content closer to users to reduce latency.

---

Latency and Throughput

• Latency: Time taken to process a request.
• Throughput: Number of requests processed in a given time.

---

Caching in System Design

• Improves performance by storing frequently accessed data.

What is API Gateway?

• Manages APIs and facilitates communication between microservices.

Message Queues

• Enables asynchronous communication between components.

Communication Protocols

• HTTP, gRPC, WebSocket, etc.

Network Protocols and Proxies

• TCP/IP, DNS, Reverse Proxy, etc.

---

Unified Modeling Language (UML)

• Standard for visualizing system design.

---

Databases in Designing Systems

Which Database to Choose – SQL or NoSQL

• SQL: Structured data, complex queries.
• NoSQL: Flexible schema, high scalability.

File and Database Storage Systems

• File Storage: Stores files in directories.
• Database Storage: Organized data in tables or collections.

Database Replication in System Design

• Copies data across multiple servers for reliability.

Database Sharding

• Splits data across multiple servers for scalability.

Block, Object, and File Storage

• Block: High performance, low latency.
• Object: Scalability for unstructured data.
• File: Hierarchical structure.

Normalization Process in DBMS

• Organizes data to reduce redundancy.

Denormalization in Databases

• Optimizes read performance by adding redundancy.

---

Low-Level Design (LLD)

What is Low-Level Design or LLD?

• Focuses on implementation details.

Object-Oriented Programming (OOP) Concepts

• Encapsulation, Inheritance, Polymorphism, Abstraction.

Data Structures and Algorithms for System Design

• Hashmaps, Trees, Queues, Graphs, etc.

Object-Oriented Analysis and Design

• Breaks down problems into objects and their interactions.

---

Difference Between Authentication and Authorization

• Authentication: Verifies identity.
• Authorization: Grants permissions.

---

Design Patterns

• Singleton, Factory, Observer, etc.

Code Optimization Techniques

• Improve performance and readability.

Unit Testing

• Tests individual components.

Integration Testing

• Tests interactions between components.

---

CI/CD: Continuous Integration and Continuous Delivery

• Automates testing and deployment processes.

Introduction to Modularity and Interfaces

• Breaks systems into independent modules.

---

Essential Security Measures in System Design

• Encryption, Firewalls, Authentication, etc.

---

Interview Questions & Answers of System Design

Popular Examples

• URL Shortening Service
• Design Dropbox
• Design Twitter
• System Design Netflix
• Uber System Architecture
• Design BookMyShow
• Facebook Messenger
• WhatsApp Messenger
• Instagram

---

Tips for System Design Interviews

How to Crack System Design Round

1. Understand the requirements.
2. Create a high-level design.
3. Address scalability and reliability.
4. Discuss trade-offs.

5 Tips to Crack Low-Level System Design Interviews

1. Understand OOP principles.
2. Focus on modularity.
3. Practice design patterns.
4. Write clean, optimized code.
5. Review example designs.

Common System Design Concepts for Interview Preparation

1. Scalability.
2. Consistency.
3. High Availability.
4. Caching.
5. Load Balancing.

Steps to Approach Object-Oriented Design Questions

1. Understand the problem.
2. Identify key objects.
3. Define relationships.
4. Use appropriate design patterns.
5. Create UML diagrams.

@The WebSpace