Question 135 of 144
SK0-005 troubleshooting Practice Question
A server technician has just replaced a failed hard drive in a RAID 5 array. After inserting the new drive, the array begins rebuilding, but after 10 minutes, the rebuild fails and the array status shows 'degraded' again. Which of the following is the MOST likely cause?
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 new drive is larger than the other drives in the array.
Option A is correct. In RAID 5, if the replacement drive is larger than the other drives, some RAID controllers will fail the rebuild because they cannot utilize the extra capacity or may encounter metadata inconsistencies. Option B is unlikely because enterprise drives are typically hot-swappable. Option C (firmware differences) can sometimes cause issues but is less common than size mismatch. Option D (rotational speed) rarely prevents a rebuild.
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 new drive has a higher rotational speed.
Why it's wrong here
Differences in rotational speed do not typically prevent a RAID rebuild; the array can function with mixed speeds.
- ✗
The new drive has a different firmware version than the other drives.
Why it's wrong here
Firmware mismatch can cause operational issues but seldom leads to a rebuild that begins successfully and then aborts.
- ✗
The new drive is not hot-swappable and was inserted while the server was on.
Why it's wrong here
Most server-class drives are hot-swappable; inserting a non-hot-swappable drive usually causes immediate damage or recognition failure, not a rebuild that starts and then fails.
- ✓
The new drive is larger than the other drives in the array.
Why this is correct
A larger drive may cause rebuild failure because the RAID controller cannot properly integrate a disk with greater capacity than existing members.
Quick reference
RAID Level Comparison
| RAID Level | Min Disks | Fault Tolerance | Read | Write | Usable Capacity |
|---|---|---|---|---|---|
| RAID 0 | 2 | None | Excellent | Excellent | 100% |
| RAID 1 | 2 | 1 disk | Good | Moderate | 50% |
| RAID 5 | 3 | 1 disk | Good | Moderate | 67–94% |
| RAID 6 | 4 | 2 disks | Good | Lower | 50–88% |
| RAID 10 | 4 | 1 disk per mirror | Excellent | Good | 50% |
RAID is not a backup strategy — it protects against disk failure but not against accidental deletion, ransomware, or site-level events.
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Last reviewed: Jul 26, 2026
This SK0-005 practice question is part of Courseiva's free CompTIA 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 SK0-005 exam.
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