The historical fixture assigns four equal slot ranges to A, B, A and C. Wrong-node access returns MOVED. Tagged keys share a slot, but same-primary different-slot MSET fails unchanged. Three primaries without replicas cannot replace a failed primary.

Redis Cluster splits keys across slots

Redis Cluster separates key placement from machine identity. A key maps to one of 16,384 fixed hash slots; cluster metadata maps those slots to primaries and their replicas. Adding a machine does not change the slot hash function. Operators redistribute slots, while clients discover the current topology and react to routing changes. ...

November 26, 2027 · 7 min · XB Field Notes