SK0-005 server-hardware-installation-management Practice Question
A server with a RAID 5 array of four disks reports a degraded logical drive. The technician replaces the failed disk and rebuilds the array. After the rebuild completes, the array is still degraded. 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 replacement disk has a different rotational speed than the other disks
Option B is correct because if the replacement disk is of a different speed (e.g., 10k vs 15k), the RAID controller may not accept it or the rebuild may fail, leaving the array degraded. Option A is wrong because missing a partition would not cause the array to remain degraded after rebuild; the array is at a lower level. Option C is wrong because if the firmware were outdated, the controller would likely not recognize the drive at all. Option D is wrong because the disk name in Windows would not affect the RAID status.
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 replacement disk is assigned a different drive letter in the OS
Why it's wrong here
Drive letter assignment is an OS-level configuration and does not affect the RAID array status at the controller level.
- ✗
The RAID controller firmware is outdated
Why it's wrong here
Outdated firmware would likely cause more general issues, not specifically a single replacement disk failure after rebuild.
- ✓
The replacement disk has a different rotational speed than the other disks
Why this is correct
Many RAID controllers require all drives in an array to have matching specifications; a speed mismatch can cause the rebuild to fail or the drive to be rejected.
- ✗
The replacement disk is missing a partition table
Why it's wrong here
RAID arrays operate at the disk level, not partition level. A missing partition table would not cause the array to stay degraded.
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.
Go deeper
Related to this question
Learn chapter
Physical and Logical Security Controls
Key term
RAID Levels
RAID (Redundant Array of Independent Disks) levels are different configurations that combine multiple hard drives or SSDs to improve performance, reliability, or both.
Key term
RAID 5
RAID 5 is a disk array configuration that uses block-level striping with distributed parity to provide fault tolerance and good read performance while using storage space efficiently.
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Same concept, more angles
2 more ways this is tested on SK0-005
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A RAID 5 array is degraded due to a failed disk. What is the best practice for recovery?
hard- A.Replace the failed disk and restore from backup
- ✓ B.Replace the failed disk and allow the array to rebuild automatically
- C.Replace the failed disk and perform a manual rebuild from backup
- D.Delete the logical drive and recreate the array
Why B: Option C is correct because replacing the failed disk and allowing automatic rebuild utilizes the array's redundancy and minimizes downtime. Option A destroys the existing configuration. Option B and D are unnecessary if the array can rebuild.
Variation 2. 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?
easy- A.The new drive has a higher rotational speed.
- B.The new drive has a different firmware version than the other drives.
- C.The new drive is not hot-swappable and was inserted while the server was on.
- ✓ D.The new drive is larger than the other drives in the array.
Why D: 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.
JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed July 2026 · checked against the official CompTIA exam blueprint
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.