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Consistent hashing

Maps keys to machines on a ring, so the same key always lands on the same machine and adding one moves only its share of keys.

Taught in Chapter 27: Partitioning.

More from the same chapter

• Hot partition: A partition that throttles while the others sit idle, because a hot key lives on it.
• Key-value store: A store that gets and puts values by a single key, and splits its keys across machines.
• Partition: A slice of a store's keys, served by one node at a time (with copies on others), with its own throughput budget.
• Range partitioning: Giving each partition a range of keys, which keeps range scans together and risks hot ranges.
• Virtual nodes: Many small stretches of the hash ring per machine, which spread the keys evenly under consistent hashing. A hot key still lands on one machine.