CCD-333 試験問題を無料オンラインアクセス

Which of the following statements best describes how a large (100 GB) file is stored in HDFS?

• A.The file is divided into fixed-size blocks, which are stored on multiple datanodes. Each block is replicated three times by default. Multiple blocks from the same file might reside on the same datanode.
• B.The file is replicated three times by default. Eachcopy of the file is stored on a separate datanodes.
• C.The file is divided into variable size blocks, which are stored on multiple data nodes. Each block is replicated three times by default.
• D.The master copy of the file is stored on a single datanode. The replica copies are divided into fixed-size blocks, which are stored on multiple datanodes.
• E.The file is divided into fixed-size blocks, which are stored on multiple datanodes. Each block is replicated three times by default.HDFS guarantees that different blocks from the same file are never on the same datanode.

For each intermediate key, each reducer task can emit:

• A.As many final key-value pairs as desired, but they must have the same type as the intermediate key-value pairs.
• B.As many final key-value pairs as desired, as long as all the keys have the same type and all the values have the same type.
• C.One final key-value pair per value associated with the key; no restrictions on the type.
• D.As many final key value pairs as desired. There are no restrictions on the types of those key-value pairs (i.e., they can be heterogeneous)
• E.One final key value pair per key; no restrictions on the type.

Which of the following best describes the map method input and output?

• A.It accepts a single key-value pair as input and emits a single key and list of corresponding values as output
• B.It accepts a single key-value pair as input and can emit only one key-value pair as output.
• C.It accepts a list of key-value pairs as input hut run emit only one key value pair as output.
• D.It accepts a single key-value pair as input and can emit any number of key-value pairs as output, including zero.

How does the NameNode detect that a DataNode has failed?

• A.When the NameNode fails to receive periodic heartbeats from the DataNode, it considers the DataNode as failed.
• B.When HDFS starts up, the NameNode tries to communicate with the DataNode and considers the DataNode as failed if it does not respond.
• C.The NameNode does not need to know that a DataNode has failed.
• D.The NameNode periodically pings the datanode. If the DataNode does not respond, the NameNode considers the DataNode as failed.

What is the behavior of the default partitioner?

• A.The default partitioner computes the hash of the key and divides that value modulo the number of reducers. The result determines the reducer assigned to process the key-value pair.
• B.The default partitioner assigns key value pairs to reducers based on an internal random number generator.
• C.The default partitioner computes the hash of the key. Hash values between specific ranges are associated with different buckets, and each bucket is assigned to a specific reducer.
• D.The default partitioner implements a round robin strategy, shuffling the key value pairs to each reducer in turn. This ensures an even partition of the key space.
• E.The default partitioner computes the hash of the value and takes the mod of that value with the number of reducers. The result determines the reducer assigned to process the key value pair.