System Design Visualized
Lesson 6.7

Handling failures: sloppy quorum, hinted handoff, data center outages

Play this lessonThis lesson comes with an interactive animation you can break and a chapter quiz.

Strict quorum would block reads and writes when replicas are down. Instead, use a sloppy quorum: pick the first W healthy servers for writes (and R for reads) on the ring, ignoring offline servers.

The rest of this lesson is part of Pro

Pro unlocks every lesson with its animation, code challenge and quiz, plus every interview problem. ₹299 a month or ₹1,999 a year.

See Pro

Remember it, then prove it

Create a free account to save your progress, get spaced-repetition reviews of what you miss, and design real systems in the interview simulator.

Start free