The correct command is `mdadm --create /dev/md0 --level=5 --raid-devices=3 /dev/sdb /dev/sdc /dev/sdd --metadata=1.2`, because the `--metadata=1.2` flag stores the superblock at a 4 KiB offset from the start of each disk, which the kernel reads automatically during boot to reassemble the array without manual intervention. This is essential for creating a RAID 5 that reassembles on boot, as older metadata versions (like 0.90 or 1.0) place the superblock at the end of the device, making auto-detection unreliable. On the LFCS exam, this tests your understanding of mdadm metadata versions and how they affect array discovery; a common trap is choosing `--metadata=1.0` or omitting the flag entirely, which would require manual assembly after every reboot. Remember the memory tip: “1.2 is the boot-friendly view” — the “2” in 1.2 reminds you it’s the second offset version that keeps the superblock near the start for automatic reassembly.
LFCS Storage Management Practice Question
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.
A Linux administrator needs to create a RAID 5 array using three disks: /dev/sdb, /dev/sdc, and /dev/sdd, each 2TB. The administrator wants to ensure the array can be reassembled automatically after a reboot. Which command should be used to create the array?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "which command"
Why it matters: Tests specific CLI syntax. Recall the exact command and its required context — near-synonyms and partial matches are common distractors.
Option D is correct because it uses `--metadata=1.2`, which stores the superblock at a standard 4 KiB offset from the start of each device, enabling the kernel to automatically discover and assemble the RAID array on reboot without manual intervention. RAID 5 with three disks provides striping with distributed parity, offering a balance of performance and redundancy.
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.
Correct for RAID 5 with metadata 1.2, supporting large disks and auto-assembly.
Clue confirmation
The clue word "which command" in the question point toward this answer.
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 choose `--metadata=0.90` (option A) because it is older and familiar, but they overlook that it does not support automatic reassembly on boot, which is explicitly required in the question.
Detailed technical explanation
How to think about this question
The metadata version determines where the superblock is placed on the disk: version 0.90 places it at the end (last 2 sectors), while version 1.2 places it at a 4 KiB offset from the start, which is within the range the kernel scans during boot (typically the first 64 KiB). In a real-world scenario, using `--metadata=1.2` allows the array to be automatically assembled by the kernel's `md` driver without needing an explicit `mdadm --assemble --scan` or a properly configured `mdadm.conf`, which is critical for systems that may have disks reordered or added after a reboot.
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: mdadm --create /dev/md0 --level=5 --raid-devices=3 /dev/sdb /dev/sdc /dev/sdd --metadata=1.2 — Option D is correct because it uses `--metadata=1.2`, which stores the superblock at a standard 4 KiB offset from the start of each device, enabling the kernel to automatically discover and assemble the RAID array on reboot without manual intervention. RAID 5 with three disks provides striping with distributed parity, offering a balance of performance and redundancy.
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: "which command". Tests specific CLI syntax. Recall the exact command and its required context — near-synonyms and partial matches are common distractors.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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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.
Question Discussion
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