This LFCS practice question tests your understanding of storage management. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Which two commands can be used to create an ext4 filesystem on a Linux block device? (Choose two.)
fsck.ext4 /dev/sdb1
Why wrong: Checks a filesystem, does not create.
mke2fs -j /dev/sdb1
Why wrong: Creates ext3, not ext4.
mke2fs -t ext4 /dev/sdb1
Creates ext4 using the -t ext4 option.
tune2fs -O extents /dev/sdb1
Why wrong: Modifies an existing filesystem, does not create one.
mkfs.ext4 /dev/sdb1
Creates an ext4 filesystem directly.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
mke2fs -t ext4 /dev/sdb1
Both `mke2fs -t ext4` and `mkfs.ext4` are valid commands to create an ext4 filesystem. `mke2fs` is the underlying tool for creating ext2/ext3/ext4 filesystems, and the `-t ext4` flag explicitly sets the filesystem type to ext4. `mkfs.ext4` is a wrapper script that calls `mke2fs` with the appropriate options for ext4, making it a direct and commonly used alternative.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
fsck.ext4 /dev/sdb1
Why it's wrong here
Checks a filesystem, does not create.
mke2fs -j /dev/sdb1
Why it's wrong here
Creates ext3, not ext4.
mke2fs -t ext4 /dev/sdb1
Why this is correct
Creates ext4 using the -t ext4 option.
Related concept
Read the scenario before looking for a memorised answer.
tune2fs -O extents /dev/sdb1
Why it's wrong here
Modifies an existing filesystem, does not create one.
mkfs.ext4 /dev/sdb1
Why this is correct
Creates an ext4 filesystem directly.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
The trap here is that candidates may confuse `mke2fs -j` (which creates ext3) with a command that creates ext4, or think `tune2fs` can create a filesystem, when it only modifies existing ones.
Detailed technical explanation
Under the hood, `mke2fs` writes the superblock, group descriptors, inode table, and block bitmap structures to the block device. When creating an ext4 filesystem, it enables features like extents, flex_bg, and uninit_bg by default (depending on the version of e2fsprogs). A real-world scenario: if you mistakenly use `mke2fs -j` on a device intended for ext4, you will get an ext3 filesystem without extents support, which can degrade performance for large files and reduce maximum filesystem size.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
What to study next
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FAQ
Storage Management — This question tests Storage Management — Read the scenario before looking for a memorised answer..
The correct answer is: mke2fs -t ext4 /dev/sdb1 — Both `mke2fs -t ext4` and `mkfs.ext4` are valid commands to create an ext4 filesystem. `mke2fs` is the underlying tool for creating ext2/ext3/ext4 filesystems, and the `-t ext4` flag explicitly sets the filesystem type to ext4. `mkfs.ext4` is a wrapper script that calls `mke2fs` with the appropriate options for ext4, making it a direct and commonly used alternative.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 25, 2026
This LFCS practice question is part of Courseiva's free Linux Foundation certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the LFCS exam.
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