Quick Answer
The answer is the free -m command, because it displays system memory usage in megabytes while explicitly showing separate columns for buffers and cache, which are essential for diagnosing memory pressure that can cause slow queries on a database server. On the CompTIA Linux+ XK0-005 exam, this question tests your ability to select the correct memory analysis tool from common options like free, vmstat, and top; a frequent trap is choosing free without the -m flag, which defaults to kilobytes and can mislead an administrator reviewing memory in MB. The exam emphasizes that buffers and cache represent disk and filesystem metadata that the kernel can reclaim under memory pressure, so ignoring them gives an incomplete picture of available memory. To remember this, think "free -m for memory in MB, with buffers and cache in plain view."
This XK0-005 practice question tests your understanding of troubleshooting. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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 database server is experiencing slow queries. The administrator wants to analyze system memory usage. Which command shows memory usage in megabytes and includes information about buffers and cache?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "which command"
Why it matters: Tests specific CLI syntax. Recall the exact command and its required context — near-synonyms and partial matches are common distractors.
free -m
Correct: Displays memory in MB with buffers/cache.
top -b
Why wrong: Shows processes, not memory summary in MB.
cat /proc/meminfo
Why wrong: Shows raw memory info in kilobytes.
vmstat
Why wrong: Shows memory statistics but not in MB by default.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
free -m
The 'free -m' command displays system memory usage in megabytes, explicitly showing separate columns for buffers and cache, which are critical for diagnosing slow queries caused by memory pressure. This makes it the correct choice for the administrator's need to analyze memory usage with buffer/cache details in MB.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
free -m
Why this is correct
Correct: Displays memory in MB with buffers/cache.
Clue confirmation
The clue word "which command" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
top -b
Why it's wrong here
Shows processes, not memory summary in MB.
cat /proc/meminfo
Why it's wrong here
Shows raw memory info in kilobytes.
vmstat
Why it's wrong here
Shows memory statistics but not in MB by default.
Common exam traps
CompTIA often tests the distinction between commands that show memory in raw kernel units (like /proc/meminfo in kB) versus those that offer user-friendly output with specific columns (like free -m), leading candidates to choose /proc/meminfo for its detail while missing the explicit requirement for megabytes and buffer/cache breakdown.
Trap categories for this question
Command / output trap
Shows processes, not memory summary in MB.
Detailed technical explanation
The 'free' command reads data from /proc/meminfo and formats it into human-readable units; the '-m' flag converts values from kilobytes to mebibytes (MiB). The 'buffers' column represents temporary storage for block device I/O, while 'cache' refers to page cache used by the kernel to speed up file access, both of which are critical for database performance—high cache usage can indicate efficient memory utilization, while low available memory may force swapping.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A practitioner preparing for the XK0-005 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. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Troubleshooting — study guide chapter
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FAQ
Troubleshooting — This question tests Troubleshooting — Read the scenario before looking for a memorised answer..
The correct answer is: free -m — The 'free -m' command displays system memory usage in megabytes, explicitly showing separate columns for buffers and cache, which are critical for diagnosing slow queries caused by memory pressure. This makes it the correct choice for the administrator's need to analyze memory usage with buffer/cache details in MB.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Yes — watch for: "which command". Tests specific CLI syntax. Recall the exact command and its required context — near-synonyms and partial matches are common distractors.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 30, 2026
This XK0-005 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 XK0-005 exam.
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