sysdesign-question-bank

name	sysdesign-question-bank
description	Catalog of 12 canonical system design problems from Alex Xu Vol.1 with the book's canned numbers (DAU/QPS/storage), key decisions, common traps, and expected rubric categories per problem. Loaded explicitly by sysdesign-design when a topic is chosen — not auto-injected. Each problem has its own file under problems/. Vol.2 problems (proximity service, distributed message queue, etc.) are NOT in this catalog — see _vol2-gap.md.
disable-model-invocation	true

sysdesign-question-bank

12 canonical problems from Alex Xu Vol.1 (Korean edition: 가상 면접 사례로 배우는 대규모 시스템 설계 기초). Each problem file contains the book's canned numbers, core decisions, common traps, and deep-dive topics — used by sysdesign-design as the Clarifying starting point.

How sysdesign-design uses this

When the user picks a topic ("채팅 시스템 만들고 싶어"), sysdesign-design loads the matching problems/<slug>.md and offers the book's canned numbers as the starting assumptions. User then adjusts (e.g., "100M DAU로 가자").

Catalog

Slug	Title (KO / EN)	Type	Scale class
rate-limiter	처리율 제한 장치의 설계 / Rate Limiter	Mock-ready (warm-up)	medium
consistent-hashing	안정 해시 설계 / Consistent Hashing	Building-block reference	large
key-value-store	키-값 저장소 설계 / Key-Value Store	Building-block reference	large
unique-id-generator	분산 시스템을 위한 유일 ID 생성기 설계 / Unique ID Generator	Mock-ready	large
url-shortener	URL 단축기 설계 / URL Shortener	Mock-ready	medium-to-large
web-crawler	웹 크롤러 설계 / Web Crawler	Mock-ready	large
notification-system	알림 시스템 설계 / Notification System	Mock-ready	large
news-feed	뉴스 피드 시스템 설계 / News Feed System	Mock-ready	large
chat-system	채팅 시스템 설계 / Chat System	Mock-ready	large
search-autocomplete	검색어 자동완성 시스템 / Search Autocomplete	Mock-ready	large
youtube	유튜브 설계 / YouTube	Mock-ready	large
google-drive	구글 드라이브 설계 / Google Drive	Mock-ready	large

Type definitions:

• Mock-ready: Suitable as a standalone interview problem — bounded scope, clear requirements, tractable in 45–60 min.
• Building-block reference: Primarily an infrastructure concept used as a sub-component in other problems; rarely posed as a standalone interview topic.

Recommended learner sequence

1. rate-limiter — bounded scope; algorithm comparison + Redis
2. unique-id-generator — short; introduces Snowflake
3. url-shortener — classic; API + hashing + caching + HTTP
4. consistent-hashing — pure infra concept; prereq for KV store and sharding
5. key-value-store — deepest theory (CAP, quorum, vector clock, gossip, Merkle); requires consistent-hashing
6. notification-system — multi-provider fan-out, queue decoupling
7. web-crawler — queue design, dedup (bloom), politeness
8. news-feed — fan-out write vs read tradeoff; foundational social
9. search-autocomplete — trie + batch pipeline
10. chat-system — real-time, stateful servers, message ordering
11. google-drive — chunking, delta sync, strong consistency, storage tiering
12. youtube — transcoding DAG, CDN optimization, pre-signed URLs, live streaming (most complex)

Topic → trigger phrase mapping (for sysdesign-design)

User says	Topic slug
처리율 제한 / rate limiter / rate limiting / API throttling	rate-limiter
안정 해시 / consistent hashing / consistent hash	consistent-hashing
키-값 저장소 / key-value store / KV store / DynamoDB clone / Cassandra clone	key-value-store
유일 ID / unique ID / distributed ID / snowflake / ID 생성기	unique-id-generator
URL 단축기 / url shortener / tinyurl / bit.ly	url-shortener
웹 크롤러 / web crawler / web crawling / 크롤러	web-crawler
알림 시스템 / notification system / push notification / 푸시 알림	notification-system
뉴스 피드 / news feed / 피드 / social feed / Instagram feed	news-feed
채팅 시스템 / 채팅 서비스 / chat / messenger / WhatsApp clone / 메신저	chat-system
검색어 자동완성 / search autocomplete / typeahead / 자동완성	search-autocomplete
유튜브 / YouTube / 동영상 스트리밍 / video streaming	youtube
구글 드라이브 / Google Drive / 파일 스토리지 / cloud storage / file sync	google-drive

Recurring cross-problem decisions (quick reference)

Decision	Problems
Consistent hashing for partitioning	consistent-hashing, key-value-store, url-shortener, search-autocomplete
Cache layer (Redis/Memcached)	rate-limiter, url-shortener, news-feed, chat-system, search-autocomplete, youtube, google-drive
Message queue for decoupling	notification-system, news-feed, youtube, google-drive, web-crawler
Fan-out (write vs read vs hybrid)	news-feed, notification-system, chat-system
CDN for static/media	youtube, google-drive, news-feed
Bloom filter for dedup	web-crawler, key-value-store
WebSocket / real-time	chat-system, notification-system

Vol.2 gap

The following Vol.2 problems are NOT in this catalog (the Korean PDFs locally available are both Vol.1):

• Proximity Service / Nearby Friends / Google Maps / Distributed Message Queue / Metrics Monitoring / Ad Click Aggregation / Hotel Reservation

See problems/_vol2-gap.md for the full list and acquisition note.

Source: alex-xu-vol2-problems.md (researched 2026-05-03); Alex Xu Vol.1 (2020), Korean translation Insight Press (2021).