LPIC-1 Devices, Filesystems and FHS Practice Question
An administrator needs to create a new ext4 filesystem on /dev/sdb1 and wants to reserve 2% of the blocks for the root user. Which command should be used?
⚠ Common exam trap
It's easy for candidates to confuse `-m` (reserved block percentage) with `-r` (revision level) or assume `tune2fs` can be used to create a filesystem, when in fact `tune2fs` only modifies existing filesystems.
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 -m 2 /dev/sdb1
The `-m` flag in `mkfs.ext4` specifies the percentage of filesystem blocks reserved for the root user (superuser). By default, ext4 reserves 5% of blocks; using `-m 2` reduces this to 2%, as required. This command creates a new ext4 filesystem on `/dev/sdb1` with the specified reserved block percentage.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
mkfs.ext4 -m 2 /dev/sdb1
Why this is correct
Correct: -m specifies reserved blocks percentage.
- ✗
tune2fs -m 2 /dev/sdb1
Why it's wrong here
tune2fs modifies an existing filesystem, but the filesystem must already exist.
- ✗
mke2fs -r 2 /dev/sdb1
Why it's wrong here
-r is not a valid option for mke2fs.
- ✗
mkfs.ext4 -R 2 /dev/sdb1
Why it's wrong here
-R is used for RAID options, not reserved blocks.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This LPIC-1 practice question is part of Courseiva's free LPI 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 LPIC-1 exam.