Which statement about managed sharding is correct?

Which statement about managed sharding is correct?

• A. DynamoDB hashes the partition key to internal partitions.
• B. Cassandra uses modulo hashing with no virtual nodes.
• C. MongoDB uses fixed shards with manual balancing.
• D. All three databases require manual shard configuration.

Answer: (A)

Managed sharding means the system handles how data is split and moved across storage nodes, so you don’t have to configure partitions yourself. In DynamoDB, the partition key is hashed to determine which internal partitions store the item. This hashing and distribution are automatic, so sharding is fully managed by the service. Cassandra, on the other hand, uses a token-based ring with a partitioner (often Murmur3) and typically employs virtual nodes to spread load; this is not simply modulo hashing with no virtual nodes, so that description isn’t accurate for Cassandra. MongoDB’s sharding involves a cluster with shards and chunks, with an automatic balancer that moves chunks to keep data and load balanced. It isn’t about fixed shards with manual balancing. Because DynamoDB handles the sharding internally by hashing the partition key, the statement about it being hashed to internal partitions reflects managed sharding.

Managed sharding means the system handles how data is split and moved across storage nodes, so you don’t have to configure partitions yourself. In DynamoDB, the partition key is hashed to determine which internal partitions store the item. This hashing and distribution are automatic, so sharding is fully managed by the service.

Cassandra, on the other hand, uses a token-based ring with a partitioner (often Murmur3) and typically employs virtual nodes to spread load; this is not simply modulo hashing with no virtual nodes, so that description isn’t accurate for Cassandra.

MongoDB’s sharding involves a cluster with shards and chunks, with an automatic balancer that moves chunks to keep data and load balanced. It isn’t about fixed shards with manual balancing.

Because DynamoDB handles the sharding internally by hashing the partition key, the statement about it being hashed to internal partitions reflects managed sharding.