Hashing

Turning keys into positions: how hash functions place data on machines, and how to move as little as possible when the machines change.

Explainers

• Consistent Hashing — Add a machine to a sharded system and plain hash-mod-N reshuffles almost everything. Consistent hashing puts the nodes on the same ring as the keys — walk clockwise to the owner — so a membership change moves only one arc, and virtual nodes even out the load. Drawn, computed, and animated.