Block storage and replication in Hadoop - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to specify the default replication factor in Hadoop configuration.

Hadoop

conf.set("dfs.replication", [1])

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A"1"

B"5"

C"3"

D"0"

Attempts:

3 left

💡 Hint

Common Mistakes

Setting replication factor to 0 disables replication, which is not recommended.

Using replication factor 1 means no copies, risking data loss.

The default replication factor in Hadoop is usually set to 3 to ensure data reliability.

2fill in blank

medium

Complete the code to get the block size from Hadoop configuration.

Hadoop

long blockSize = conf.getLong("dfs.blocksize", [1]);

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A67108864

B262144

C33554432

D134217728

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing block size with replication factor.

Using too small or too large block sizes without reason.

The default block size in Hadoop is 128 MB, which is 134217728 bytes.

3fill in blank

hard

Fix the error in the code to correctly retrieve the replication factor as an integer.

Hadoop

int replication = conf.getInt("dfs.replication", [1]);

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A3

B"3"

Cnull

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Passing a string instead of an integer causes a type error.

Using null as default causes runtime exceptions.

The getInt method expects an integer default value, not a string.

4fill in blank

hard

Fill both blanks to create a dictionary comprehension that maps block IDs to their replication counts, filtering blocks with replication less than 3.

Hadoop

block_replications = {block_id: replication for block_id, replication in blocks.items() if replication [1] [2]

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A>=

B<

C3

D2

Attempts:

3 left

💡 Hint

Common Mistakes

Using >= instead of < changes the filter logic.

Using wrong threshold number.

The comprehension filters blocks with replication less than 3.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension that maps block IDs to their sizes for blocks with size greater than 128 MB.

Hadoop

large_blocks = { [1] : [2] for [3] in blocks.items() if size > 134217728 }

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Ablock_id

Bsize

C(block_id, size)

Dblock

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong variable names causing errors.

Not unpacking the tuple correctly.

The comprehension unpacks each block tuple into block_id and size, then maps block_id to size for large blocks.