Consistent Hashing Playground: Modulo Hashing Moves 83% of Keys When a Server Joins, Jump Hash 17%

Mon, 05 Oct 2026 00:00:00 +0000

Five cache servers share 100,000 keys. Traffic grows, and you add a sixth. With the obvious rule, hash the key and divide by the number of servers, 83% of the keys now belong somewhere else. Most of them move between servers that never changed. For a cache that’s a wave of misses landing on the database at once. For a store it’s a mountain of data copied across the network for no reason.

Consistent Hashing on KeyValueStore.com

Consistent Hashing Playground: Modulo Hashing Moves 83% of Keys When a Server Joins, Jump Hash 17%