4.3 Replication

Replication 이 필요한 이유

• 고가용성 및 내구성을 달성하기 위해, Dynamo 는 여러 호스트에서 데이터를 복제합니다.

Replication 방식

• 각 데이터 항목은 N개의 호스트에서 복제됩니다. 여기서 N 은 인스턴스별로 구성된 매개변수입니다.

• 각 Key 는 coordinator 노드에 할당됩니다.

The coordinator is in charge of the replication of the data items that fall within its range. In addition to locally storing each key within its range, the coordinator replicates these keys at the N-1 clockwise successor nodes in the ring. This results in a system where each node is responsible for the region of the ring between it and its Nth predecessor. In Figure 2, node B replicates the key k at nodes C and D in addition to storing it locally. Node D will store the keys that fall in the ranges (A, B], (B, C], and (C, D].