This EX200 practice question tests your understanding of operate running systems. 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.
Exhibit
[root@server ~]# df -h /var
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/rootvg-var 20G 19G 1G 95% /var
[root@server ~]# du -sh /var/log
5.2G /var/log
Refer to the exhibit. Which command would free up the most space immediately?
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.
Clue: "immediately / without restart"
Why it matters: Time or reboot constraint — the correct answer must take effect right away without requiring a reboot or reload.
Exhibit
[root@server ~]# df -h /var
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/rootvg-var 20G 19G 1G 95% /var
[root@server ~]# du -sh /var/log
5.2G /var/log
A
yum clean all
Why wrong: Cleans package cache, which is not located in /var/log.
B
rm -rf /var/log/*
Why wrong: Deletes all logs, including important ones, and is not recommended.
C
journalctl --vacuum-size=500M
Reduces journal log size to 500MB, freeing significant space.
D
logrotate -f /etc/logrotate.conf
Why wrong: Rotates logs but doesn't guarantee space reduction if old logs are kept.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
journalctl --vacuum-size=500M
Option C is correct because `journalctl --vacuum-size=500M` immediately reduces the size of the systemd journal logs to 500 MB by deleting older journal files. This frees up space in `/var/log/journal` without affecting other log files or requiring a restart of the journal service.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
yum clean all
Why it's wrong here
Cleans package cache, which is not located in /var/log.
✗
rm -rf /var/log/*
Why it's wrong here
Deletes all logs, including important ones, and is not recommended.
✓
journalctl --vacuum-size=500M
Why this is correct
Reduces journal log size to 500MB, freeing significant space.
Clue confirmation
The clue words "which command", "immediately / without restart" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
logrotate -f /etc/logrotate.conf
Why it's wrong here
Rotates logs but doesn't guarantee space reduction if old logs are kept.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Red Hat exams often test the distinction between commands that immediately free space versus those that only reorganize or cache-clean, leading candidates to choose `yum clean all` or `logrotate` without realizing that journal logs are typically the largest consumer of disk space on a default RHEL system.
Detailed technical explanation
How to think about this question
The systemd journal stores logs in binary journal files under `/var/log/journal` (if persistent storage is enabled). The `--vacuum-size` flag uses the journal's internal cleanup mechanism to remove the oldest journal files until the total size is below the specified limit, which is immediate and safe because journal files are self-contained and can be deleted without affecting active logging. In contrast, `logrotate` works with text-based log files and relies on post-rotation scripts (e.g., `kill -HUP`) to signal daemons to reopen log files, which can delay space reclamation if the daemon does not release the file handle.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A practitioner preparing for the EX200 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
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Operate running systems — This question tests Operate running systems — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: journalctl --vacuum-size=500M — Option C is correct because `journalctl --vacuum-size=500M` immediately reduces the size of the systemd journal logs to 500 MB by deleting older journal files. This frees up space in `/var/log/journal` without affecting other log files or requiring a restart of the journal service.
What should I do if I get this EX200 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "which command", "immediately / without restart". Tests specific CLI syntax. Recall the exact command and its required context — near-synonyms and partial matches are common distractors.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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