DATABASE FUNDAMENTALS
BASICS OF BIG DATA
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Filenames, blocks and checksums
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Blocks and heartbeat messages
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Filenames, block locations
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Blocks and block locations
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Detailed explanation-1: -HDFS Namenode stores meta-data i.e. number of data blocks, file name, path, Block IDs, Block location, no. of replicas, and also Slave related configuration. This meta-data is available in memory in the master for faster retrieval of data.
Detailed explanation-2: -The hdfs-site. xml file contains information such as the value of replication data, namenode path, and datanode paths of your local file systems.
Detailed explanation-3: -HDFS comprises of 3 important components-NameNode, DataNode and Secondary NameNode. HDFS operates on a Master-Slave architecture model where the NameNode acts as the master node for keeping a track of the storage cluster and the DataNode acts as a slave node summing up to the various systems within a Hadoop cluster.
Detailed explanation-4: -The NameNode is the centerpiece of an HDFS file system. It keeps the directory tree of all files in the file system, and tracks where across the cluster the file data is kept. It does not store the data of these files itself.
Detailed explanation-5: -Namenode maps these blocks to DataNodes. The data nodes store and retrieve blocks as instructed by the NameNode.