Scaling
Consistent Hashing
Map keys and nodes onto a ring; a key belongs to the first node clockwise. Adding a node moves only ~1/N of keys.
Why interviewers ask about it
`hash(key) % N` remaps ~91% of keys when going from 10 to 11 nodes. Virtual nodes are required, not optional, for even distribution.
Related terms
This term is part of the free System Design interview preparation module - browse the full glossary for every definition.