SK0-005 troubleshooting Practice Question

Exhibit

[  234.567890] sd 0:0:0:0: [sda] tag#0 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE
[  234.567895] sd 0:0:0:0: [sda] tag#0 Sense Key : Medium Error [current]
[  234.567899] sd 0:0:0:0: [sda] tag#0 Add. Sense: Unrecovered read error - auto reallocate failed
[  234.567903] sd 0:0:0:0: [sda] tag#0 CDB: Read(10) 28 00 00 00 00 00 00 00 08 00
[  234.567906] blk_update_request: I/O error, dev sda, sector 12345678

Refer to the exhibit. A Linux server started reporting I/O errors to its local disk. The administrator runs `dmesg` and sees the output shown. Which of the following is the MOST likely cause of the errors?

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 disk has a bad sector that cannot be remapped.

Option B is correct. The 'Medium Error' sense key along with 'Unrecovered read error - auto reallocate failed' indicates a physical bad sector that the drive could not reallocate. Option A would typically produce a different hostbyte (e.g., DID_NO_CONNECT). Option C, outdated firmware, rarely causes medium errors. Option D, filesystem corruption, would manifest as filesystem-level errors, not SCSI sense codes.

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 disk has a bad sector that cannot be remapped.
Why this is correct
The Sense Key 'Medium Error' and additional sense 'auto reallocate failed' explicitly indicate an unreadable sector that the drive's internal remapping could not fix.
✗
The filesystem on /dev/sda is corrupted.
Why it's wrong here
Filesystem corruption leads to errors like 'Input/output error' at the OS level, but the dmesg output here shows a low-level SCSI read error, not a filesystem issue.
✗
The SCSI cable is loose.
Why it's wrong here
A loose cable would more likely result in transport errors (hostbyte=DID_NO_CONNECT or DID_BAD_TARGET), not a Medium Error from the drive itself.
✗
The RAID controller firmware is outdated.
Why it's wrong here
Firmware issues do not typically generate 'Medium Error' sense codes; they would more likely cause driver or communication errors.

About these practice questions

Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →

How Courseiva writes practice questions · Editorial policy

Last reviewed: Jul 26, 2026

Question Discussion

Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.

Loading comments…

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.