Vnode (virtual node)
The technique of having each physical node be responsible for many small segments ("virtual nodes") on the consistent hash ring instead of a single one. It gives more even data distribution, smoother rebalancing, and better load spreading.
Problem with plain consistent hashing: with just one point per node on the ring, the distribution becomes uneven (chance gives some nodes much larger ranges), and when a node is added/removed a large contiguous chunk moves to/from a single neighbor. Vnodes give each physical node hundreds of small ranges scattered across the ring → statistically even distribution, and on a topology change the load/offload is spread over many nodes at once (faster, smoother). Bonus: nodes with different capacity can be assigned different numbers of vnodes (heterogeneous clusters). Standard in Cassandra (num_tokens) and DynamoDB-like systems. An important practical improvement to consistent hashing. Related to consistent hashing and leaderless replication.