Reddit/Quora Software System Design
0 likes1,164 views
This document outlines a 5-step methodology for designing a system like Reddit or Quora: 1) Define use cases, assumptions, and constraints. 2) Perform back-of-the-envelope calculations for database design and daily traffic. 3) Design core components like APIs and services for key use cases like posting topics and reactions. 4) Create a high-level design diagram. 5) Scale the design through techniques like load balancing, database sharding, caching, and DNS.
Reddit/Quora Software System Design
- 1. Methodology for Reddit/Quora 1. 5 Step Process 1.1. Use cases, assumptions, constraints 1.2. Back of envelope calculations 1.3. Design core components 1.4. High level design 1.5. Scale the design
- 2. Reddit/Quora Step 1a: Use Cases ● Functional requirements (use cases) ○ Users posts a topic ○ User reacts to a topic (comment, like) ○ Notification service when a reaction is on a topic ○ User search a topic ● Nonfunctional requirements ○ High availability
- 3. Reddit/Quora Step 1b: Constraints, Assumptions ● Uneven traffic ● 10 million users/daily ● 100,000 topics ● 33% of users reacts daily ○ 3:1 read-write
- 4. Reddit/Quora Step 2a: Back of envelope calculations ● Database design ○ Users ■ Id ■ Name ■ Topics_associated ○ Topics ■ Id ■ Topic_name ■ Created_at ■ Participants_progress (object with users_id and timestamps) ○ Reactions ■ Id ■ Reaction_type ■ Content ■ Topic_id ■ User_id ■ Created_at
- 5. Reddit/Quora Step 2b: Back of envelope calculations ● Daily traffic ○ 10 million users/daily ○ 100,000 reactions/sec ○ 33% of users reacts daily ■ 3:1 read-write ● Storage ○ Tables of Users (~50 bytes), Topics (~100 bytes), Reactions (~350 bytes) ■ ~500 bytes * 100,000 reactions/sec ● 50 MB/s
- 6. Reddit/Quora Step 3: Design core components ● Use case #1: User create a topic ○ Server, Write API, database ● Use case #2: Users react to a topic ○ Server, Write API, Read API, database, object store ● Use case #3: Notification service ○ Server, Write API, database, notification service ● Use case #4: Users search for a topic ○ Server, database, Search API, search service
- 7. Reddit/Quora Step 4: High Level Design
- 8. Reddit/Quora Step 5: Scale the Design ● High availability ○ Add load balancers, DB shards, caches, DNS