SK0-005 security-disaster-recovery Practice Question
Exhibit
[12345.678] sd 0:0:0:0: [sda] Unhandled sense code [12345.678] sd 0:0:0:0: [sda] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE [12345.678] sd 0:0:0:0: [sda] Sense Key : Medium Error [current] [12345.678] sd 0:0:0:0: [sda] Add. Sense: Unrecovered read error - auto reallocate failed [12345.678] end_request: I/O error, dev sda, sector 123456
Refer to the exhibit. An administrator is reviewing logs after a server experienced performance issues and unexpected shutdowns. Based on the log entries, which component is MOST likely failing?
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
✓
Hard disk drive
The log entries show multiple SCSI medium errors, unrecovered read errors, and auto-reallocation failures on device sda, which are classic signs of a failing hard disk drive (Option B). A RAID controller (A) would typically show different errors, RAM (C) would cause memory-related errors, and a power supply (D) would trigger power event logs.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
RAID controller
Why it's wrong here
RAID controller issues might present as disk array failures or rebuild logs, not specific medium errors on a single drive.
- ✗
RAM module
Why it's wrong here
Faulty RAM typically causes memory parity errors or kernel panics, not I/O errors with sense key reporting.
- ✓
Hard disk drive
Why this is correct
Medium errors and failed sector reallocation are direct indicators of physical hard disk drive failure.
- ✗
Power supply
Why it's wrong here
Power supply failures often generate power-related log entries (e.g., voltage warnings), not disk I/O errors.
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
Storage Management (RAID, SAN, NAS)
Key term
PSU
A PSU converts AC mains power into regulated DC voltages required by computer components, ensuring stable operation.
Key term
Dual In-line Memory Module
A Dual In-line Memory Module (DIMM) is a small circuit board that holds memory chips and plugs into a computer's motherboard to provide Random Access Memory (RAM).
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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.