- A
The SATA cable for the root disk is loose, causing the disk to be detected intermittently.
Why wrong: Would cause device not found, not unknown-block.
- B
The partition table on the root disk uses GPT but the BIOS is set to legacy boot.
Why wrong: This affects bootloader, not VFS mount.
- C
The initramfs image is missing the necessary tools to mount the root filesystem, e.g., missing filesystem driver.
If initramfs lacks the driver, mount fails.
- D
The root filesystem is corrupted and cannot be read by the kernel.
Corruption can cause mount failure.
- E
The root filesystem is located on a device that requires a kernel module not included in the initramfs.
If the driver for the root device is missing, kernel can't mount.
Question 220 of 513
LFCS Storage Management Practice Question
This LFCS practice question tests your understanding of storage management. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Which THREE of the following are potential causes for a system failing to boot with 'Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block'?
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
✓
The initramfs image is missing the necessary tools to mount the root filesystem, e.g., missing filesystem driver.
Option C is correct because the kernel relies on the initramfs to load necessary filesystem drivers (e.g., ext4, XFS, Btrfs) and tools (e.g., fsck, lvm) to mount the root filesystem. If the initramfs is missing the required driver for the root filesystem type, the kernel will fail with 'VFS: Unable to mount root fs' because it cannot access the block device containing the root partition.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The SATA cable for the root disk is loose, causing the disk to be detected intermittently.
Why it's wrong here
Would cause device not found, not unknown-block.
- ✗
The partition table on the root disk uses GPT but the BIOS is set to legacy boot.
Why it's wrong here
This affects bootloader, not VFS mount.
- ✓
The initramfs image is missing the necessary tools to mount the root filesystem, e.g., missing filesystem driver.
Why this is correct
If initramfs lacks the driver, mount fails.
Related concept
Read the scenario before looking for a memorised answer.
- ✓
The root filesystem is corrupted and cannot be read by the kernel.
Why this is correct
Corruption can cause mount failure.
Related concept
Read the scenario before looking for a memorised answer.
- ✓
The root filesystem is located on a device that requires a kernel module not included in the initramfs.
Why this is correct
If the driver for the root device is missing, kernel can't mount.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse a missing initramfs driver (which causes a kernel panic at mount time) with a corrupted filesystem (which would produce a different error, such as 'mount: unknown filesystem type' or 'I/O error') or with bootloader configuration issues (which prevent the kernel from loading at all).
Detailed technical explanation
How to think about this question
The initramfs is a temporary root filesystem loaded into memory by the bootloader; it contains kernel modules (e.g., for storage controllers, filesystem drivers) and user-space tools (e.g., udev, lvm, mdadm) needed to assemble and mount the real root filesystem. If the root filesystem uses a driver that is compiled as a module (e.g., ext4 as a module) and that module is missing from the initramfs, the kernel will panic when it cannot mount the root device. This is commonly seen when rebuilding the initramfs with 'dracut' or 'mkinitcpio' without including the necessary storage or filesystem modules.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A practitioner preparing for the LFCS exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
- →
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Learn the concepts, then practise the questions
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FAQ
Questions learners often ask
What does this LFCS question test?
Storage Management — This question tests Storage Management — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The initramfs image is missing the necessary tools to mount the root filesystem, e.g., missing filesystem driver. — Option C is correct because the kernel relies on the initramfs to load necessary filesystem drivers (e.g., ext4, XFS, Btrfs) and tools (e.g., fsck, lvm) to mount the root filesystem. If the initramfs is missing the required driver for the root filesystem type, the kernel will fail with 'VFS: Unable to mount root fs' because it cannot access the block device containing the root partition.
What should I do if I get this LFCS question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Last reviewed: Jul 4, 2026
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.
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