LFCS Storage Management Practice Question
A system administrator needs to create a new ext4 filesystem on /dev/sdb1 with a reserved block percentage of 2% instead of the default 5%. Which command should be used?
⚠ Common exam trap
It's easy for candidates to confuse `-m` (reserved block percentage) with `-r` (revision number) or `-R` (RAID stride), or they incorrectly choose `tune2fs` which modifies an existing filesystem rather than creating a new one.
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` sets the reserved block percentage for the superuser, and specifying `-m 2` overrides the default of 5% to reserve only 2% of the blocks on the new ext4 filesystem on /dev/sdb1.
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 sets reserved blocks percentage.
- ✗
mkfs.ext4 -R 2 /dev/sdb1
Why it's wrong here
Incorrect: -R is not a valid option for mkfs.ext4.
- ✗
mkfs.ext4 -r 2 /dev/sdb1
Why it's wrong here
Incorrect: -r is for RAID stride.
- ✗
tune2fs -m 2 /dev/sdb1
Why it's wrong here
Incorrect: tune2fs modifies an existing filesystem, not creation.
Go deeper
Related to this question
About these practice questions
Courseiva writes every LFCS question from scratch — 507 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.