Each slave node in your cluster has four 2 TB hard drives installed (4x2TB). You set a value of the dfs.du.datanode.received parameter to 100GB on each slave node. How does this alter HDFS block…

The correct answer is B. 100 GB on each hard drive may not be used to store HDFS blocks. dfs.datanode.du.reserved This many bytes will be left free on the volumes used by the DataNodes (see dfs.data.dir). As our drives are dedicated to Hadoop we left this at 0 but if the drives host other stuff as well set this to an appropriate value. If you save other stuff than…

Configuration

Question

Each slave node in your cluster has four 2 TB hard drives installed (4x2TB). You set a value of the dfs.du.datanode.received parameter to 100GB on each slave node. How does this alter HDFS block storage?

Options

A25 GB on each hard drive may not be used to store HDFS Blocks
B100 GB on each hard drive may not be used to store HDFS blocks
CAll Hard drives may be used to store HDFS blocks as long as at least 100GB in total is available on the node
Da maximum of 100GB on each hard drive may be used to store HDFS blocks

How the community answered

(37 responses)

A
14% (5)
B
76% (28)
C
3% (1)
D
8% (3)

Explanation

dfs.datanode.du.reserved This many bytes will be left free on the volumes used by the DataNodes (see dfs.data.dir). As our drives are dedicated to Hadoop we left this at 0 but if the drives host other stuff as well set this to an appropriate value. If you save other stuff than Hadoop data on the disks make sure to set dfs.datanode.du.reserved.

Topics

#DataNode configuration#disk space reservation#HDFS storage

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