5-Hour System Design Course: Complete Interview Preparation

5-Hour System Design Course: Complete Interview Preparation

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Timestamps:
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INTRODUCTION & REQUIREMENTS
0:00:00 Welcome & Course Overview
0:02:12 Why This Framework Works
0:03:34 Interview Framework: Start with Requirements
0:06:30 Functional Requirements
0:09:15 Non-Functional Requirements
0:11:45 Scale Requirements (500M DAU)
0:14:05 Out-of-Scope Features
0:17:10 Requirements Summary

CAPACITY ESTIMATION & ARCHITECTURE
0:19:00 Why Capacity Estimation Matters
0:21:30 Traffic Calculations (QPS)
0:24:00 Read Traffic: 100K QPS
0:26:00 Write Traffic: 1K QPS
0:27:30 Read:Write Ratio (100:1)
0:30:00 Storage Estimation (73 PB/Year)
0:35:00 Bandwidth Estimation (231 GB/sec)
0:39:00 High-Level Architecture Overview
0:44:00 Microservices Architecture
0:47:00 Data Flow Walkthrough
0:50:00 Cache Hit vs Cache Miss Paths
0:52:00 Architecture Summary

DATABASE DESIGN
0:54:00 Database Design Overview
0:57:00 Users Table Schema & Indexes
1:02:00 Posts Table Schema
1:07:00 Follows Table (Social Graph)
1:11:00 Likes & Comments Tables
1:14:00 SQL vs NoSQL Decision
1:17:00 Database Sharding (User ID, 1000 Shards)
1:20:00 Cross-Shard Queries
1:23:00 Resharding Strategies

API DESIGN
1:24:00 API Design Principles (RESTful)
1:27:00 User Management APIs
1:31:00 Post APIs
1:34:00 Feed API
1:37:00 Social Interaction APIs
1:40:00 Cursor-Based Pagination
1:42:00 JWT Authentication & Rate Limiting
1:44:00 Error Handling

FEED GENERATION ALGORITHM
1:45:00 The Feed Generation Challenge
1:48:00 Why Naive Approaches Fail
1:51:00 Fan-Out on Write (Push Model)
1:55:00 Fan-Out on Read (Pull Model)
1:59:00 Hybrid Approach (Instagram's Solution)
2:03:00 Celebrity Problem (10K Follower Threshold)
2:06:00 Ranking Algorithm
2:09:00 Complete Feed Generation Flow
2:12:00 Latency Breakdown & Optimization

MEDIA STORAGE & CDN
2:15:00 Media Storage Challenge (73 PB/Year)
2:18:00 Why Database Storage Fails
2:21:00 Object Storage Solution (S3/Azure Blob)
2:25:00 Storage Hierarchy & Organization
2:29:00 Async Image Processing Pipeline
2:33:00 Thumbnail Generation (3 Sizes)
2:36:00 CDN Strategy (80% Cache Hit)
2:39:00 Lifecycle Policies (Hot → Warm → Cold)
2:42:00 Cost Optimization

SCALING PATTERNS
2:44:00 Scaling Overview
2:47:00 Application Tier: Stateless Servers
2:52:00 Load Balancing & Health Checks
2:57:00 Auto-Scaling Configuration
3:02:00 Database Tier Scaling
3:08:00 Cache Tier: Redis Clustering
3:13:00 Async Processing with Queues
3:17:00 Rate Limiting (Token Bucket)
3:21:00 Sliding Window Algorithm

TRADE-OFFS & COST ANALYSIS
3:23:00 Key Trade-Offs Overview
3:26:00 Consistency vs Availability (CAP)
3:30:00 SQL vs NoSQL Trade-Offs
3:34:00 Fan-Out Strategies Comparison
3:38:00 Sync vs Async Processing
3:42:00 Denormalization for Performance
3:47:00 Cost Analysis (~$57M/Month)
3:52:00 Cost Optimization Strategies
3:57:00 Infrastructure Savings ($40-50M/Year)

INTERVIEW STRATEGY
4:00:00 45-Minute Interview Breakdown
4:04:00 Interview Tips: What to Do
4:09:00 Think Out Loud & Ask Questions
4:13:00 Drawing Diagrams Effectively
4:17:00 Mistake #1: Skipping Requirements
4:20:00 Mistake #2: No Capacity Estimation
4:23:00 Mistake #3: Ignoring Trade-Offs
4:26:00 Mistake #4: Surface-Level Design
4:29:00 Mistake #5: Not Adapting to Hints
4:32:00 Mistake #6: Buzzword Overload
4:35:00 Mistake #7: No Error Handling

PRACTICE & PREPARATION
4:37:00 6-8 Week Study Plan
4:41:00 Week 1-2: Fundamentals
4:45:00 Week 3-4: Practice Problems
4:49:00 Week 5-6: Mock Interviews
4:53:00 Week 7-8: Refinement
4:57:00 Interview Day Checklist
5:01:00 Recommended Resources
5:05:00 Course Summary & Final Thoughts

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About me:
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I'm Mukul Raina, a Senior Software Engineer and Tech Lead at Microsoft, with a Master's in Computer Science from the University of Oxford. On this channel, I create technical deep dives on System Design and ML/AI architectures.

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