PK0-005 Practice Question: Basics of IT Infrastructure and IT Project Management
A large organization is deploying a new ERP system. The infrastructure team provisions a cluster of virtual machines for the application and a separate database server. During load testing with typical user loads, the database server shows high I/O wait times. The storage administrator confirms that the storage array has sufficient capacity and the disks are healthy. The hypervisor shows no CPU or memory pressure. Which of the following is the most likely cause of the high I/O wait?
⚠ Common exam trap
Many candidates assume high I/O wait always means a disk hardware failure or capacity issue, but the question explicitly states disks are healthy and capacity is sufficient, steering the answer toward a RAID-level misconfiguration that causes excessive write overhead.
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
✓
Misconfigured RAID level, such as using RAID 5 for a write-intensive workload.
RAID 5 uses parity-based striping, which incurs a write penalty (each write requires four I/O operations: read old data, read old parity, write new data, write new parity). For a write-intensive workload like an ERP database, this overhead causes high I/O wait times even when disks are healthy and capacity is sufficient. The correct answer is C because the misconfigured RAID level directly explains the observed symptom.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Network bandwidth saturation between the database and application servers.
Why it's wrong here
Network saturation would show as network latency or packet loss, not as high I/O wait on the database server.
- ✗
Insufficient memory on the database server causing paging.
Why it's wrong here
Insufficient memory would cause paging and high memory pressure, but the hypervisor shows no memory pressure, so this is unlikely.
- ✓
Misconfigured RAID level, such as using RAID 5 for a write-intensive workload.
Why this is correct
RAID 5 requires extra parity calculations on writes, increasing I/O wait; RAID 10 would be more appropriate for write-heavy databases.
- ✗
CPU overutilization on the database server.
Why it's wrong here
CPU overutilization would show as high CPU usage, not high I/O wait. The hypervisor reports no CPU pressure.
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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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This PK0-005 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 PK0-005 exam.