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Foundations and Building Blocks
Scaling (vertical vs horizontal); load balancers and their algorithms; caching (where, what, invalidation, eviction); SQL vs NoSQL and how to choose.
Module Content
Scaling Basics — Vertical vs Horizontal
The first system design decision. When to scale up (bigger box) vs scale out (more boxes), and the trade-offs of each. FIND_VIDEO: search 'vertical vs horizontal scaling explained' — recommended channel: ByteByteGo / Gaurav Sen. Aim for 10 min or under.
Recap — When and How to Scale
Vertical scaling, horizontal scaling, and the architectural shifts each requires.
Load Balancers
Distribute requests across servers. Algorithms (round robin, least connections, hashing), L4 vs L7, and the failure modes. FIND_VIDEO: search 'load balancer system design interview' — recommended channel: ByteByteGo / Gaurav Sen. Aim for 10 min or under.
Recap — Load Balancer Strategies and Gotchas
LB algorithms, layer 4 vs layer 7, sticky sessions, health checks, and what breaks at scale.
Caching
The single biggest performance lever. Where to cache, what to cache, how to invalidate, and the eviction policies that matter. FIND_VIDEO: search 'caching strategies system design' — recommended channel: ByteByteGo / Hussein Nasser. Aim for 10 min or under.
Recap — Cache Patterns, Invalidation, Eviction
Cache layers (browser, CDN, app, DB), the three caching patterns, eviction policies, and the hardest problem in computer science.
SQL vs NoSQL
The most-asked DB question in interviews. Strengths, weaknesses, and concrete signals for choosing one over the other. FIND_VIDEO: search 'SQL vs NoSQL when to use which' — recommended channel: ByteByteGo / Hussein Nasser. Aim for 11 min or under.
Recap — Choosing Between SQL and NoSQL
What each type is good for, the major NoSQL flavors (KV, document, column, graph), and how to pick.