Which system uses consistent hashing with virtual nodes to distribute data across its ring?

Which system uses consistent hashing with virtual nodes to distribute data across its ring?

• A. Cassandra uses consistent hashing with virtual nodes.
• B. DynamoDB uses virtual nodes.
• C. Redis uses virtual nodes by default.
• D. CDNs use fixed hash slots.

Answer: (A)

Consistent hashing on a ring with virtual nodes lets you distribute data evenly and rebalance with minimal data movement. In this approach, the hash space forms a circle, keys map to points on that circle, and each physical node owns multiple token ranges—these are the virtual nodes. With many vnodes per node, data distribution becomes finer-grained and load balancing improves; when a node is added or removed, only the neighboring token ranges shift, keeping disruption small. Cassandra adopts this exact design by using a large number of virtual nodes per physical node, which makes scaling out and rebalancing efficient and predictable. DynamoDB, Redis, and CDNs use different partitioning schemes and don’t employ the virtual-node ring model in the way Cassandra does, so they aren’t described as distributing data across a ring with virtual nodes.

Consistent hashing on a ring with virtual nodes lets you distribute data evenly and rebalance with minimal data movement. In this approach, the hash space forms a circle, keys map to points on that circle, and each physical node owns multiple token ranges—these are the virtual nodes. With many vnodes per node, data distribution becomes finer-grained and load balancing improves; when a node is added or removed, only the neighboring token ranges shift, keeping disruption small.

Cassandra adopts this exact design by using a large number of virtual nodes per physical node, which makes scaling out and rebalancing efficient and predictable. DynamoDB, Redis, and CDNs use different partitioning schemes and don’t employ the virtual-node ring model in the way Cassandra does, so they aren’t described as distributing data across a ring with virtual nodes.