The answer is that the drives are overheating due to continuous I/O, causing the system to freeze. When a RAID 5 array experiences heavy disk I/O—such as during parity calculations or rebuilds—the sustained read/write activity generates significant heat, which can exceed the thermal threshold of the hard drives. This triggers thermal throttling, where the drives temporarily halt operations to cool down, or the controller locks up, resulting in the observed freezes. On the CompTIA A+ Core 1 220-1201 exam, this question tests your understanding of thermal management in storage subsystems, often as a trap where test-takers mistakenly blame SATA speed mismatches (3 Gb/s drives on a 6 Gb/s controller) or controller incompatibility. Remember, SATA speeds are backward-compatible and won’t cause freezing—heat is the hidden culprit. Memory tip: “RAID 5 rebuilds run hot; if it freezes, check the spot.”
220-1101 Storage and RAID Troubleshooting Practice Question
This 220-1201 practice question tests your understanding of storage and raid troubleshooting. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A technician is configuring a RAID 5 array with three 1 TB HDDs on a motherboard RAID controller. After setup, the array works but the system occasionally freezes during heavy disk I/O. The drives are all SATA 3 Gb/s and the motherboard supports SATA 6 Gb/s. What is the most likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The drives are overheating due to continuous I/O.
Mixing SATA speeds (3 Gb/s drives on a 6 Gb/s controller) is generally backward-compatible and should not cause freezes. The freezing during heavy I/O suggests a thermal issue, as RAID 5 rebuilds and heavy writes generate significant heat. Overheating can cause drives to throttle or the controller to lock up.
Key principle: NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
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 SATA 3 Gb/s drives are bottlenecking the SATA 6 Gb/s controller.
Why it's wrong here
A speed mismatch would limit throughput but not cause system freezes; it would just be slower.
✓
The drives are overheating due to continuous I/O.
Why this is correct
RAID 5 with heavy I/O generates heat; if cooling is inadequate, drives can overheat and cause the system to freeze or throttle.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Static NAT maps one inside address to one outside address.
✗
The RAID controller's firmware is outdated.
Why it's wrong here
Outdated firmware might cause bugs, but the most direct cause of freezing during heavy I/O is thermal throttling.
✗
The stripe size is set too small.
Why it's wrong here
Stripe size affects performance but does not typically cause system freezes; it would just result in slower I/O.
Common exam traps
Common exam trap: NAT rules depend on direction and matching traffic
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Detailed technical explanation
How to think about this question
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
KKey Concepts to Remember
Static NAT maps one inside address to one outside address.
PAT allows many inside hosts to share one public address using ports.
Inside local and inside global describe the private and translated addresses.
NAT ACLs identify traffic for translation, not always security filtering.
TExam Day Tips
→Identify inside and outside interfaces first.
→Check whether the scenario needs static NAT, dynamic NAT or PAT.
→Do not confuse NAT matching ACLs with normal packet-filtering intent.
Key takeaway
NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Real-world example
How this comes up in practice
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this 220-1201 question in full detail.
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related 220-1201 NAT questions on configuration and troubleshooting.
Storage and RAID Troubleshooting — This question tests Storage and RAID Troubleshooting — Static NAT maps one inside address to one outside address..
What is the correct answer to this question?
The correct answer is: The drives are overheating due to continuous I/O. — Mixing SATA speeds (3 Gb/s drives on a 6 Gb/s controller) is generally backward-compatible and should not cause freezes. The freezing during heavy I/O suggests a thermal issue, as RAID 5 rebuilds and heavy writes generate significant heat. Overheating can cause drives to throttle or the controller to lock up.
What should I do if I get this 220-1201 question wrong?
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related 220-1201 NAT questions on configuration and troubleshooting.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Static NAT maps one inside address to one outside address.
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