LFCS Storage Management Practice Question
A system administrator is troubleshooting a server that fails to boot because the root filesystem, which is on an LVM logical volume, cannot be found. The administrator suspects that the initramfs does not include the necessary LVM modules. Which command should be used to rebuild the initramfs for the currently running kernel on a Debian-based system?
⚠ Common exam trap
The trap here is assuming that initramfs tools are universal across distributions, when each family has its own default command.
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
✓
update-initramfs -u
On Debian-based systems, the initramfs is managed with update-initramfs. Running update-initramfs -u regenerates the image for the current kernel, incorporating any needed modules such as LVM. Other tools like dracut or mkinitrd are used on different distributions and are not the default on Debian, and grub-mkconfig only updates the bootloader configuration.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
grub-mkconfig -o /boot/grub/grub.cfg
Why it's wrong here
grub-mkconfig regenerates the GRUB configuration file, which controls the boot menu and kernel parameters. It does not rebuild the initramfs. While updating GRUB can be part of boot troubleshooting, it will not add LVM modules to the initramfs. The issue described requires rebuilding the initramfs, not the GRUB configuration.
- ✓
update-initramfs -u
Why this is correct
update-initramfs -u updates the initramfs for the currently running kernel on Debian-based systems. It regenerates the initramfs image using the current configuration, which should include LVM modules if the system is configured to use LVM. This is the correct command to ensure the boot image can activate LVM volumes.
- ✗
dracut -f
Why it's wrong here
dracut -f rebuilds the initramfs on Red Hat-based systems, not Debian-based ones. While dracut can be installed on Debian, it is not the default tool. The standard Debian command is update-initramfs. Using dracut on a Debian system without proper configuration could create a non-bootable image.
- ✗
mkinitrd -f /boot/initrd.img-$(uname -r)
Why it's wrong here
mkinitrd is an older tool used on some distributions like SUSE and older Red Hat, but it is not the standard on modern Debian systems. The syntax shown may not work correctly, and the command is not present by default on Debian. The correct tool for Debian is update-initramfs.
Go deeper
Related to this question
About these practice questions
Courseiva writes every LFCS question from scratch — 406 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 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.