How does consistent hashing fix that?
Both nodes and keys map to positions on a circle. A key belongs to the next node encountered walking clockwise. When you add a node, it lands on the circle between two existing nodes. Only keys in that arc rebalance. The other arcs stay pointing to the same node.
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When 87% of Your Cache VanishesConsistent hashing maps nodes and keys to a circle, so adding a server moves only 1/N of keys instead of almost all of them.
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