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FC0-U71 Practice Question: A hospital's IT team manages a virtualized server…
A hospital's IT team manages a virtualized server hosting a patient records database. The server has one physical processor with 6 cores, 32 GB of RAM, and a RAID 5 array of three 1 TB HDDs. The virtual machine (VM) running the database is configured with 2 vCPUs, 8 GB RAM, and a 500 GB virtual disk stored on the RAID array. Users report that database queries are taking much longer than usual. The host server shows CPU utilization at 20%, memory at 60%, and the disk queue length frequently stays above 5. Which of the following is the most likely cause of the performance issue?
⚠ Common exam trap
CompTIA often tests the misconception that high disk queue length is always caused by insufficient memory, but here memory is adequate and the queue is due to slow HDDs in RAID 5, not paging.
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
✓
Disk I/O bottleneck
The disk queue length consistently exceeding 5 indicates that I/O requests are waiting for the storage subsystem, which is a classic sign of a disk I/O bottleneck. The RAID 5 array of three 1 TB HDDs provides limited IOPS compared to SSDs, and the single virtual disk on this array cannot keep up with the database workload. Even though CPU and memory utilization are moderate, the high queue length shows the disks are the limiting factor.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Disk I/O bottleneck
Why this is correct
A high disk queue length indicates that the storage subsystem is overloaded, causing slow response times.
- ✗
Network bandwidth limitation
Why it's wrong here
No network issues are reported or observed.
- ✗
Insufficient memory
Why it's wrong here
Memory usage is 60%, leaving ample headroom.
- ✗
Insufficient CPU resources
Why it's wrong here
CPU utilization is only 20%, so the CPU is not a bottleneck.
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 FC0-U71 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 FC0-U71 exam.