Question 138 of 144
SK0-005 troubleshooting Practice Question
An organization has a server with a hardware RAID 5 array consisting of four 2 TB SAS drives. The server hosts a critical database and is configured with a hot spare. During routine monitoring, the storage administrator discovers that one drive has failed and the hot spare has automatically taken over, with the array currently rebuilding. However, the rebuild process repeatedly fails at approximately 30% completion, and the RAID controller logs show I/O errors on the hot spare drive. The failed drive was replaced with an identical model from inventory, and the rebuild was restarted, but it again fails at the same point. All other drives show healthy SMART status, and the server's firmware and RAID controller firmware are up to date. The database is still online and functioning, but the array is running in a degraded state, putting data at risk. The server is located in a remote data center without onsite staff, and a maintenance window is scheduled in three days.
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
✓
Run a low-level diagnostic on the replacement drive and verify its firmware revision against the RAID controller's compatibility list.
Option D is correct because the repeated rebuild failure at the same point, with I/O errors on the new drive, suggests either a physical media error on the new drive or an incompatibility issue. Running a manufacturer diagnostic and checking the firmware version of the spare can reveal if the drive is faulty or needs a firmware update to match the controller’s expectations. Option A (replacing the RAID controller) is unlikely needed when the issue seems confined to a single drive slot. Option B (performing a consistency check) is useful but won't resolve the rebuild failure; it could even cause more wear. Option C (breaking and recreating the array) is the most drastic and will destroy all data, requiring restore from backup.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Initiate a full array consistency check to find and repair any parity mismatches before rebuilding.
Why it's wrong here
A consistency check verifies data integrity but does not fix a bad drive. It may stress the array further without solving the rebuild problem.
- ✓
Run a low-level diagnostic on the replacement drive and verify its firmware revision against the RAID controller's compatibility list.
Why this is correct
The symptoms point to a problem with the physical replacement drive. Verifying its health and firmware compatibility is the most targeted and safe next step.
- ✗
Back up all data immediately, then break and recreate the RAID 5 array from scratch, restoring the backup.
Why it's wrong here
This extreme measure should be a last resort. It involves full downtime and risk of backup integrity, and does not address why the new drive isn't working.
- ✗
Replace the RAID controller card and its cache module, then attempt the rebuild again.
Why it's wrong here
RAID controller failure is possible but less likely when other drives function normally and the error is localized to the hot spare. It's an expensive and disruptive step.
Visual reference
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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