JN0-106 Operational Monitoring and Maintenance Practice Question
A Juniper device is running out of disk space on the /var partition. Which command can be used to check disk usage?
⚠ Common exam trap
The trap here is that candidates familiar with other operating systems might expect a command like 'show system disk-space' or confuse memory with storage, but Junos uses the specific phrase 'storage' for disk usage monitoring.
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
✓
show system storage
The correct command to check disk usage on a Juniper device is 'show system storage'. This command displays detailed information about disk partitions, including total, used, and available space, as well as the percentage of usage for each mounted filesystem, such as /var. It is the standard operational mode command for monitoring storage utilization in Junos OS.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
show system storage
Why this is correct
This is the correct command. It provides a detailed view of every mounted filesystem on the device, including the /var partition, with columns for total space, used space, available space, and mount points. The output is analogous to the UNIX 'df -k' utility, making it the standard operational command to diagnose disk-full conditions in Junos.
- ✗
show system disk-space
Why it's wrong here
This is not a recognized Junos CLI command. The hierarchical operational command tree does not contain a 'disk-space' option under 'show system', and attempting to execute it will produce an error such as 'error: unknown command'. The only valid way to inspect disk usage is via 'show system storage'.
- ✗
show system memory
Why it's wrong here
This command reports on system memory (RAM) utilization, such as the amount of physical memory in use, the amount free, and other memory pool statistics. It does not display any information about filesystem or partition storage usage, so it is completely irrelevant to a scenario where the /var partition is filling up.
- ✗
show system resource
Why it's wrong here
This is not a valid operational command in Junos; the closest valid command is 'show system resources' (plural), which shows CPU, memory, and buffer utilization but still does not include disk or filesystem information. Since the question is specifically about disk space on /var, this command neither exists in the intended form nor provides the needed storage output.
Go deeper
Related to this question
About these practice questions
One of 326 original JN0-106 practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This JN0-106 practice question is part of Courseiva's free Juniper Networks 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 JN0-106 exam.