Distributed Systems Lab
Eleven ideas that only matter once you have more than one machine.
Consistent Hashing
Scaling without reshuffling everything.
Keys map to the next server clockwise on the ring. Add a node and see how few keys actually have to move.
A
B
C
D
4 nodes, 8 keys, all stable.
Compare that to naive hash(key) % N hashing — adding one node there would remap almost every key at once.