Multi-leader replication.

also: multi-master replication · multi-leader · multi-master · active-active · multi-region active-active

Several nodes (often one per region) accept writes and replicate to each other, so concurrent writes can conflict.

the two-minute refresher

Users write to their nearest leader: low-latency writes in every region.
A region can keep working when it is cut off from the others.
Two leaders can change the same record at once: you need conflict resolution.
Options: last-write-wins, merging, CRDTs, or routing each record to one home region.

also: multi-master replication · multi-leader · multi-master · active-active · multi-region active-active

Several nodes (often one per region) accept writes and replicate to each other, so concurrent writes can conflict.

Users write to their nearest leader: low-latency writes in every region.
A region can keep working when it is cut off from the others.
Two leaders can change the same record at once: you need conflict resolution.
Options: last-write-wins, merging, CRDTs, or routing each record to one home region.