The answer is the `request system storage cleanup` command, which is the correct choice because it safely reclaims disk space on the /var partition by removing only old log files, core dumps, and temporary files that Junos has determined are no longer needed, preserving system stability. This command is a key topic on the JNCIA-Junos exam under system maintenance and troubleshooting, often appearing in scenarios where the /var partition is nearly full and an administrator must avoid risky manual deletions. A common trap is choosing `file delete` or `rm` commands, which can remove critical system files; the exam tests your understanding that Junos provides a built-in, safe cleanup mechanism. For a memory tip, think of the command as a "safe janitor" — it only cleans what the system knows is trash, so remember "request system storage cleanup" as your go-to for a full /var partition.
JNCIA-JUNOS Operational Monitoring and Maintenance Practice Question
This JNCIA-JUNOS practice question tests your understanding of operational monitoring and maintenance. 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
Output of 'show system storage':
Filesystem Size Used Avail Capacity Mounted on
/dev/da0s1a 512M 100M 412M 19% /
/dev/da0s1e 512M 200M 312M 39% /config
/dev/da0s1f 2.0G 1.8G 200M 90% /var
Refer to the exhibit. An administrator notices the /var partition is nearly full. Which command can be used to safely reclaim disk space?
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.
Output of 'show system storage':
Filesystem Size Used Avail Capacity Mounted on
/dev/da0s1a 512M 100M 412M 19% /
/dev/da0s1e 512M 200M 312M 39% /config
/dev/da0s1f 2.0G 1.8G 200M 90% /var
A
request system reboot
Why wrong: Rebooting does not free disk space. It may temporarily clear some temp files, but it is not effective and causes downtime.
B
request system storage cleanup
The 'request system storage cleanup' command safely removes temporary files, old logs, core files, and software images from /var and other partitions, freeing up space without risking critical data.
C
delete /var/log/messages
Why wrong: Deleting /var/log/messages removes the main log file, which may be needed for troubleshooting. It is not a safe or recommended method.
D
request system software delete
Why wrong: This command removes installed software packages, which is not appropriate for reclaiming disk space from logs and temporary files.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
request system storage cleanup
The 'request system storage cleanup' command safely removes old log files, core dumps, and other temporary files that are no longer needed, freeing up space on the /var partition without risking system stability. This is the recommended Junos method for reclaiming disk space because it targets only files that can be safely deleted.
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.
✗
request system reboot
Why it's wrong here
Rebooting does not free disk space. It may temporarily clear some temp files, but it is not effective and causes downtime.
✓
request system storage cleanup
Why this is correct
The 'request system storage cleanup' command safely removes temporary files, old logs, core files, and software images from /var and other partitions, freeing up space without risking critical data.
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.
✗
delete /var/log/messages
Why it's wrong here
Deleting /var/log/messages removes the main log file, which may be needed for troubleshooting. It is not a safe or recommended method.
✗
request system software delete
Why it's wrong here
This command removes installed software packages, which is not appropriate for reclaiming disk space from logs and temporary files.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates may think manually deleting log files (option C) is safe and effective, but Junos relies on its own cleanup mechanisms to avoid breaking log rotation or losing important diagnostic data.
Trap categories for this question
Command / output trap
This command removes installed software packages, which is not appropriate for reclaiming disk space from logs and temporary files.
Detailed technical explanation
How to think about this question
The 'request system storage cleanup' command invokes the Junos 'jclean' process, which scans directories like /var/tmp, /var/crash, /var/log, and /var/core for files that are safe to remove, such as old rotated logs, core dumps, and package installation leftovers. It respects file retention policies (e.g., keeping the last few log rotations) and does not touch active system files. In real-world scenarios, this command is crucial for preventing /var partition exhaustion that could cause logging failures or system instability.
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 JNCIA-JUNOS 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.
Operational Monitoring and Maintenance — This question tests Operational Monitoring and Maintenance — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: request system storage cleanup — The 'request system storage cleanup' command safely removes old log files, core dumps, and other temporary files that are no longer needed, freeing up space on the /var partition without risking system stability. This is the recommended Junos method for reclaiming disk space because it targets only files that can be safely deleted.
What should I do if I get this JNCIA-JUNOS 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". 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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