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What Is the Purpose of HDFS Block Replication Factor in Hadoop Storage?
Learn why HDFS replicates data blocks in Hadoop. Understand how block replication improves fault tolerance and high availability by keeping multiple copies across DataNodes, ensuring data stays accessible during failures.
Question
Why does HDFS replicate data blocks?
A. To reduce the size of the datasetTo reduce the size of the dataset
B. To support SQL-style queries
C. To increase the speed of computation
D. To provide fault tolerance and high availability of data
Answer
D. To provide fault tolerance and high availability of data
Explanation
HDFS replicates each data block across multiple DataNodes so the file remains accessible even if a disk, node, or network path fails. By keeping multiple copies (commonly a default replication factor such as 3), HDFS can transparently read from another replica and maintain data availability while the system replaces missing replicas in the background.