Consistent Hashing

Noun · Development

Definitions

  1. A hashing technique where adding or removing a node only requires redistributing 1/n of the keys (where n is the number of nodes), compared to traditional hashing which redistributes nearly all keys. Nodes are placed on a virtual ring, and keys are assigned to the nearest node clockwise. Used by DynamoDB, Cassandra, and consistent-hash load balancers.

    In plain English: A way to distribute data across servers so that adding or removing a server only moves a small fraction of the data.

    Example: "With consistent hashing, adding a fourth cache node only moves 25% of keys — without it, 75% of your cache misses on resize."

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