CCD-470 Free Dumps Study Materials
Question 5: Which describes how a client reads a file from HDFS?
A. The client queries the NameNode for the block location(s). The NameNode returns the block
location(s) to the client. The client reads the data directory off the DataNode(s).
B. The client queries all DataNodes in parallel. The DataNode that contains the requested data
responds directly to the client. The client reads the data directly off the DataNode.
C. The client contacts the NameNode for the block location(s). The NameNode then queries the
DataNodes for block locations. The DataNodes respond to the NameNode, and the NameNode
redirects the client to the DataNode that holds the requested data block(s). The client then reads
the data directly off the DataNode.
D. The client contacts the NameNode for the block location(s). The NameNode contacts the
DataNode that holds the requested data block. Data is transferred from the DataNode to the
NameNode, and then from the NameNode to the client.
Correct Answer: C