Hadoop Distributed File System (HDFS) DATA-SCIENCE-OPTIMIZE Practice Questions (Page 2)

Questions 6–10

1. 6application · medium

   A DataNode in an HDFS cluster has failed and will be offline for several hours. The cluster has a replication factor of 3. What will happen to the blocks that were stored on the failed DataNode?

   • AThe blocks will remain unavailable until the DataNode comes back online.
   • BThe blocks will be permanently deleted and must be restored from backup.
   • CThe NameNode will detect the missing replicas and re-replicate them to other DataNodes to maintain the replication factor.
   • DThe Secondary NameNode will take over the failed DataNode's blocks.
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2. 7foundation · easy

   Which component in HDFS is responsible for storing the actual file data as blocks on disk?

   • ASecondary NameNode
   • BDataNode
   • CNameNode
   • DResourceManager
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4. 8foundation · easy

   During a file read operation in HDFS, what is the first step a client performs?

   • AContact all DataNodes to find which ones have the file
   • BWrite a temporary file to the NameNode
   • CRead the data directly from the local disk
   • DContact the NameNode to get the locations of the file's blocks
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5. 9application · medium

   A Hadoop cluster's NameNode has failed and cannot be recovered. The cluster uses the default configuration without High Availability. The administrator has a recent checkpoint from the Secondary NameNode. What is the correct recovery procedure?

   • ARestore the NameNode metadata from the Secondary NameNode's checkpoint and restart the NameNode.
   • BPromote a DataNode to act as the new NameNode.
   • CUse the WebHDFS API to reconstruct the namespace from the data blocks.
   • DRestart the cluster and let the DataNodes rebuild the namespace from their block reports.
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6. 10foundation · easy

   What happens when a DataNode fails in an HDFS cluster?

   • AThe blocks on the failed node are automatically re-replicated to other DataNodes to maintain the replication factor
   • BThe data on the failed node is permanently lost
   • CThe client must manually copy the data to another node
   • DThe NameNode immediately shuts down to prevent data loss
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