EX200 Create and configure file systems Practice Question
A junior administrator needs to create a new Ext4 file system on the device /dev/sdb1. Which command should be used?
⚠ Common exam trap
Many candidates confuse partition management tools (fdisk, parted) with filesystem creation tools, or mistake maintenance utilities (tune2fs, fsck) for creation commands, leading them to select a wrong option that operates on a different layer of storage management.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
mkfs.ext4 /dev/sdb1
The `mkfs.ext4` command is the standard utility for creating an ext4 filesystem on a block device. It formats the partition with the ext4 journaling filesystem, writing the superblock, inode table, and journal metadata. Option D is correct because it directly invokes the mke2fs program with the ext4 filesystem type.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
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fdisk /dev/sdb1
Why it's wrong here
fdisk /dev/sdb1 is incorrect because fdisk is a disk-partitioning utility that manipulates partition tables (MBR or GPT) on a whole disk device such as /dev/sdb. Running it against the partition node /dev/sdb1 would not create an ext4 filesystem; instead, it would treat the partition itself as a disk to be repartitioned, potentially destroying existing data or the partition table itself. fdisk has no functionality for writing filesystem metadata like the ext4 superblock.
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parted /dev/sdb1
Why it's wrong here
parted /dev/sdb1 is incorrect because parted is an interactive partition editor used to create, resize, and delete partitions on a disk. Although it can tag a partition with a filesystem type string for informational purposes, it does not actually write the ext4 structures (superblock, inode table, block groups) onto the partition. Invoking parted on /dev/sdb1 would open the partition for partition-table operations, which is meaningless and could corrupt the partition's contents, but it cannot initialize a new filesystem.
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tune2fs /dev/sdb1
Why it's wrong here
tune2fs /dev/sdb1 is incorrect because tune2fs is a tool for adjusting tunable parameters on an existing ext2/ext3/ext4 filesystem, such as reserved block percentage, check intervals, or volume labels. If /dev/sdb1 is raw and has no filesystem, tune2fs will fail immediately because it cannot read a valid superblock. It is not a creation utility and would never be used as the first step to set up a filesystem.
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mkfs.ext4 /dev/sdb1
Why this is correct
mkfs.ext4 /dev/sdb1 is correct because mkfs.ext4 is a front-end to mke2fs -t ext4, which initializes a fresh ext4 filesystem on the partition. It writes the essential on-disk metadata—superblock, descriptor blocks, inode table, and journal—so the partition can be mounted and used by the Linux kernel. This is the standard command a junior administrator would run after a partition like /dev/sdb1 has been created.
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fsck /dev/sdb1
Why it's wrong here
fsck /dev/sdb1 is incorrect because fsck (filesystem check) is designed to validate and repair the consistency of an existing filesystem, not to create one. On a raw /dev/sdb1 that has never been formatted, fsck will report that the superblock is invalid and abort without writing anything. It is a maintenance tool, so running it before mkfs.ext4 would be pointless and could yield misleading error messages.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This EX200 practice question is part of Courseiva's free Red Hat 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 EX200 exam.