Backend & systems·Scaling and load management
you add a cache node and only one Nth of the keys move, instead of every key rehashing to a different server.
Consistent hashing
Also calledhash ring
Mapping keys and nodes onto a ring so that adding or removing a node relocates only a small fraction of keys. It is what makes distributed caches and shard maps survive topology changes without a total remap. Virtual nodes are the standard addition, because a plain ring distributes unevenly with few nodes.