This LFCS practice question tests your understanding of storage management. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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.
An administrator needs to configure software RAID 5 on three disks /dev/sda, /dev/sdb, /dev/sdc with a spare disk /dev/sdd. Which command correctly creates the RAID 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 A is correct because it uses the `--spare-devices=1` flag to designate `/dev/sdd` as a hot spare, while `--raid-devices=3` specifies that only three disks form the active RAID 5 array. The spare disk is listed after the active disks, which is the correct syntax for `mdadm --create`.
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.
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse `--raid-devices` with the total number of disks provided, leading them to set `--raid-devices=4` (option B) when they intend to include a spare, or they forget to specify the spare at all (option C).
Detailed technical explanation
How to think about this question
RAID 5 uses block-level striping with distributed parity, requiring at least three disks. A hot spare disk is automatically activated by the kernel's md driver when an active disk fails, minimizing rebuild time. The `--spare-devices` count must match the number of spare disks listed after the active devices; the order of device arguments is critical — active devices first, then spares.
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 small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
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 --spare-devices=1 /dev/sda /dev/sdb /dev/sdc /dev/sdd — Option A is correct because it uses the `--spare-devices=1` flag to designate `/dev/sdd` as a hot spare, while `--raid-devices=3` specifies that only three disks form the active RAID 5 array. The spare disk is listed after the active disks, which is the correct syntax for `mdadm --create`.
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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Question Discussion
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