This LFCS practice question tests your understanding of storage management. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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.
After adding a new disk and creating an ext4 filesystem on /dev/sdc1 with mke2fs, the administrator added an entry to /etc/fstab to mount it at /data. However, after reboot, the filesystem is not mounted. Which of the following is the most likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The fstab entry uses the device name /dev/sdc1 instead of UUID.
Option C is correct because when using device names like /dev/sdc1 in /etc/fstab, the kernel may assign a different device name (e.g., /dev/sdb1) after reboot due to asynchronous device discovery, causing the mount to fail. Using the filesystem's UUID (universally unique identifier) ensures persistent identification regardless of device name changes, which is a best practice for ext4 filesystems created with mke2fs.
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 filesystem superblock was corrupted.
Why it's wrong here
Superblock corruption would cause mount failures regardless of reboot, not specifically after reboot.
✗
The filesystem was not formatted correctly.
Why it's wrong here
The mke2fs command would have reported errors if formatting failed.
✓
The fstab entry uses the device name /dev/sdc1 instead of UUID.
Why this is correct
Device names can change after reboot; using UUID in fstab prevents this issue.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
The mount point /data does not exist.
Why it's wrong here
If the mount point didn't exist, the mount command would fail, but the administrator likely created it; also, the issue is after reboot.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates assume device names like /dev/sdc1 are stable across reboots, but LFCS exams test the understanding that UUIDs or LABELs are required for persistent mounts, especially after adding new disks.
Trap categories for this question
Command / output trap
The mke2fs command would have reported errors if formatting failed.
Detailed technical explanation
How to think about this question
Under the hood, Linux uses udev to dynamically create device nodes based on kernel device detection order, which can change across reboots (e.g., due to different driver loading times or hardware topology). The blkid command retrieves the UUID stored in the ext4 superblock at offset 0x468, and using UUID=... in /etc/fstab bypasses device name instability. In real-world scenarios, this is critical for SAN-attached disks or multi-path environments where device names are non-deterministic.
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.
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 fstab entry uses the device name /dev/sdc1 instead of UUID. — Option C is correct because when using device names like /dev/sdc1 in /etc/fstab, the kernel may assign a different device name (e.g., /dev/sdb1) after reboot due to asynchronous device discovery, causing the mount to fail. Using the filesystem's UUID (universally unique identifier) ensures persistent identification regardless of device name changes, which is a best practice for ext4 filesystems created with mke2fs.
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.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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