LFCS Storage Management Practice Question
A server uses LVM with volume group vg_data. The logical volume lv_app is mounted at /srv/app and is 200 GiB. The administrator adds a new 500 GiB disk, /dev/sdb, creates a physical volume on it, and extends vg_data with it. They then run lvextend -L +100G /dev/vg_data/lv_app. The filesystem is ext4. Which command must be run next to make the additional space usable without unmounting /srv/app?
⚠ Common exam trap
The trap here is assuming that extending the logical volume automatically grows the filesystem, or using a resize tool for the wrong filesystem type.
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
✓
resize2fs /dev/vg_data/lv_app
After extending the logical volume with lvextend, the ext4 filesystem must be grown to use the new space. resize2fs performs this online for ext4, keeping /srv/app mounted. xfs_growfs targets XFS, e2fsck checks but does not resize, and lvresize would further change the logical volume without touching the filesystem. The correct sequence is lvextend then resize2fs.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
lvresize -L +100G /dev/vg_data/lv_app
Why it's wrong here
lvresize adjusts the size of a logical volume, but the logical volume was already extended with lvextend. Running lvresize again with +100G would attempt to add another 100 GiB, potentially exceeding available space in vg_data. It does not resize the filesystem, so the ext4 filesystem would still be 200 GiB. This is not the required next step.
- ✗
e2fsck -f /dev/vg_data/lv_app
Why it's wrong here
e2fsck checks and repairs an ext4 filesystem. It does not resize the filesystem. Running it after lvextend will not make the additional space usable; it may even be unnecessary and time-consuming. The administrator needs a resize operation, not a consistency check, to expand the mounted filesystem.
- ✓
resize2fs /dev/vg_data/lv_app
Why this is correct
For ext4, resize2fs grows the filesystem to fill the enlarged logical volume. It can be run online on a mounted ext4 filesystem, so /srv/app remains available. Without this step, the logical volume is larger but the filesystem still reports the old size. This command is required after lvextend when using ext4.
- ✗
xfs_growfs /srv/app
Why it's wrong here
xfs_growfs is used for XFS filesystems, not ext4. Running it on an ext4 filesystem will fail because the filesystem type does not match. The scenario explicitly states the filesystem is ext4, so this command is inappropriate and will not resize the filesystem. It is a plausible distractor because both tools resize online.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Linux Foundation exam blueprint
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.