Why HDFS handles petabyte-scale storage in Hadoop - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create an HDFS directory using the Hadoop command.

Hadoop

hdfs dfs -mkdir [1]

Drag options to blanks, or click blank then click option'

A/tmp/file

B/user/data

C-ls

Ddatafile.txt

Attempts:

3 left

💡 Hint

Common Mistakes

Using a filename instead of a directory path

Using a command option instead of a path

The -mkdir command creates a directory in HDFS. Here, /user/data is a valid directory path.

2fill in blank

medium

Complete the code to set the replication factor for a file in HDFS.

Hadoop

hdfs dfs -setrep [1] /user/data/file.txt

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A0

B-rm

Cfile.txt

D3

Attempts:

3 left

💡 Hint

Common Mistakes

Using zero or negative numbers

Using command options instead of numbers

Setting replication factor to 3 means each data block is stored on 3 different nodes for fault tolerance.

3fill in blank

hard

Fix the error in the command to copy a local file to HDFS.

Hadoop

hdfs dfs -put [1] /user/data/

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A/local/path/file.txt

B-copyFromLocal

Chdfs://file.txt

D/user/data/file.txt

Attempts:

3 left

💡 Hint

Common Mistakes

Using HDFS path as source

Using command options as source

The -put command copies a local file to HDFS. The source must be a local file path.

4fill in blank

hard

Fill both blanks to create a dictionary comprehension that maps file names to their sizes if size is greater than 1000 bytes.

Hadoop

file_sizes = [1]: [2] for [1], [2] in files.items() if [2] > 1000}

Drag options to blanks, or click blank then click option'

Afilename

Bsize

Cfiles

Ditems

Attempts:

3 left

💡 Hint

Common Mistakes

Using the dictionary name as variable

Mixing keys and values

The dictionary comprehension iterates over files.items() with filename and size as key and value. It filters sizes greater than 1000.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension that maps uppercase file names to their sizes if size is less than 5000 bytes.

Hadoop

filtered_files = [1]: [2] for [3], [2] in files.items() if [2] < 5000}

Drag options to blanks, or click blank then click option'

Afilename.upper()

Bsize

Cfilename

Dfiles

Attempts:

3 left

💡 Hint

Common Mistakes

Using dictionary name as key

Not converting to uppercase

Mixing variable names

This comprehension converts file names to uppercase as keys, keeps sizes as values, and filters sizes less than 5000.