- A
An inefficient SQL query causing table scans
Why wrong: Inefficient queries can increase I/O, but the root cause is still the storage performance; however, the question asks for the most likely root cause, and without evidence of query issues, storage bottleneck is more direct.
- B
Inadequate disk spindles or a storage area network (SAN) bottleneck
I/O wait is a clear indicator of storage subsystem saturation, often due to insufficient disk spindles or SAN performance issues.
- C
Insufficient memory allocated to the database server
Why wrong: Insufficient memory leads to swapping, which increases paging activity, but the primary symptom is high paging, not I/O wait directly.
- D
Network latency between the application and database servers
Why wrong: Network latency would show as network-related delays, not disk I/O wait.
Quick Answer
The answer is inadequate disk spindles or a storage area network (SAN) bottleneck, as excessive I/O wait time on the storage subsystem directly signals that the disk array cannot service requests fast enough. This occurs because the physical disk spindles are insufficient to handle the I/O queue depth, or the SAN fabric itself is saturated, causing commands to pile up while the CPU idles. On the Certified Information Systems Auditor CISA exam, this question tests your ability to distinguish storage-layer performance issues from memory, network, or application faults—a common trap is confusing I/O wait with network latency or memory pressure. Remember that I/O wait is a disk-centric metric, not a CPU or network one. A useful memory tip: "Spindles spin, SANs swim—if I/O waits, check the disk bin."
CISA Practice Question: Information Systems Operations and Business Resilience
This CISA practice question tests your understanding of information systems operations and business resilience. 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.
An organization's online transaction processing system experienced a sudden performance degradation. The database administrator checked system resources and found excessive I/O wait time on the storage subsystem. Which of the following is the MOST likely root 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 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
Inadequate disk spindles or a storage area network (SAN) bottleneck
Option C is correct because excessive I/O wait time typically indicates that the storage system cannot keep up with the demand, often due to insufficient disk spindles or a storage bottleneck. Option A is wrong because insufficient memory usually causes high CPU usage or swapping, not directly I/O wait. Option B is wrong because network latency affects network I/O, not disk I/O. Option D is wrong because application code bugs might cause logical errors but not necessarily storage I/O issues.
Key principle: OSPF neighbour adjacency depends on matching area, hello/dead timers, network type, and authentication — IP reachability alone is not enough.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
An inefficient SQL query causing table scans
Why it's wrong here
Inefficient queries can increase I/O, but the root cause is still the storage performance; however, the question asks for the most likely root cause, and without evidence of query issues, storage bottleneck is more direct.
- ✓
Inadequate disk spindles or a storage area network (SAN) bottleneck
Why this is correct
I/O wait is a clear indicator of storage subsystem saturation, often due to insufficient disk spindles or SAN performance issues.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
OSPF neighbours must agree on key parameters.
- ✗
Insufficient memory allocated to the database server
Why it's wrong here
Insufficient memory leads to swapping, which increases paging activity, but the primary symptom is high paging, not I/O wait directly.
- ✗
Network latency between the application and database servers
Why it's wrong here
Network latency would show as network-related delays, not disk I/O wait.
Common exam traps
Common exam trap: OSPF can fail even when IP connectivity looks correct
OSPF neighbour formation depends on matching areas, timers, network type, authentication and passive-interface behaviour. Do not choose an answer only because the devices can ping.
Trap categories for this question
Command / output trap
Network latency would show as network-related delays, not disk I/O wait.
Detailed technical explanation
How to think about this question
OSPF questions usually test the details that control adjacency and route selection. Read the neighbour state, area, router ID and interface configuration before deciding what is wrong.
KKey Concepts to Remember
- OSPF neighbours must agree on key parameters.
- Router ID selection can affect neighbour relationships and LSDB output.
- OSPF cost influences the preferred path.
- A route can appear in OSPF information but not become the installed route.
TExam Day Tips
- Check area mismatch first when OSPF adjacency fails.
- Review passive interfaces when a network is advertised but no neighbour forms.
- Use show ip ospf neighbor and show ip route clues carefully.
Key takeaway
OSPF neighbour adjacency depends on matching area, hello/dead timers, network type, and authentication — IP reachability alone is not enough.
Real-world example
How this comes up in practice
A practitioner preparing for the CISA exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. OSPF neighbour adjacency depends on matching area, hello/dead timers, network type, and authentication — IP reachability alone is not enough. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Got this wrong? Here's your next step.
Review OSPF neighbour requirements — matching area type, hello and dead timers, network type, stub flags, and authentication. Study show ip ospf neighbor states (INIT, 2-WAY, FULL). Then practise related CISA OSPF questions on adjacency and route selection.
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Information Systems Operations and Business Resilience — study guide chapter
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FAQ
Questions learners often ask
What does this CISA question test?
Information Systems Operations and Business Resilience — This question tests Information Systems Operations and Business Resilience — OSPF neighbours must agree on key parameters..
What is the correct answer to this question?
The correct answer is: Inadequate disk spindles or a storage area network (SAN) bottleneck — Option C is correct because excessive I/O wait time typically indicates that the storage system cannot keep up with the demand, often due to insufficient disk spindles or a storage bottleneck. Option A is wrong because insufficient memory usually causes high CPU usage or swapping, not directly I/O wait. Option B is wrong because network latency affects network I/O, not disk I/O. Option D is wrong because application code bugs might cause logical errors but not necessarily storage I/O issues.
What should I do if I get this CISA question wrong?
Review OSPF neighbour requirements — matching area type, hello and dead timers, network type, stub flags, and authentication. Study show ip ospf neighbor states (INIT, 2-WAY, FULL). Then practise related CISA OSPF questions on adjacency and route selection.
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?
OSPF neighbours must agree on key parameters.
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Last reviewed: Jun 24, 2026
This CISA practice question is part of Courseiva's free ISACA 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 CISA exam.
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