Why disk management prevents outages in Linux CLI - Challenge Your Understanding

Challenge - 5 Problems

💻 Command Output

intermediate

Disk usage monitoring command output

You run the command df -h / on a Linux server to check disk usage of the root partition. What is the expected output format?

Linux CLI

df -h /

A

Filesystem Size Used Avail Use% Mounted on
/dev/sda1 50G 30G 20G 150% /

B

Filesystem Size Used Avail Use% Mounted on
/dev/sda1 50G 60G 20G 120% /

C

Filesystem Size Used Avail Use% Mounted on
/dev/sda1 50G 30G 20G 60% /

D

Filesystem Size Used Avail Use% Mounted on
/dev/sda1 50G 30G 20G 0% /

💡 Hint

Disk usage percentages cannot exceed 100%.

The df -h command shows disk usage with human-readable sizes. The Use% column shows the percentage of used space, which cannot be more than 100%.

🧠 Conceptual

intermediate

Why monitoring disk space prevents outages

Why does monitoring disk space usage help prevent system outages?

A Because it allows administrators to free up space before the disk is full, avoiding system crashes.

B Because it automatically deletes files when disk space is low.

C Because it increases the disk size without manual intervention.

D Because it disables all running services when disk space is low.

💡 Hint

Think about what happens when a disk is completely full.

Monitoring disk space helps admins act before the disk fills up, preventing crashes or service failures caused by no available space.

🔧 Debug

advanced

Identify the error in disk space alert script

This script is intended to alert when disk usage exceeds 90%. What error causes it to never alert?

usage=$(df / | tail -1 | awk '{print $5}' | sed 's/%//')
if [ $usage -gt 90 ]
then
  echo "Disk usage critical: $usage%"
fi

Linux CLI

usage=$(df / | tail -1 | awk '{print $5}' | sed 's/%//')
if [ $usage -gt 90 ]
then
  echo "Disk usage critical: $usage%"
fi

A The variable $usage is treated as a string, causing the numeric comparison to fail.

B The sed command removes the percent sign incorrectly, leaving a non-numeric value.

C The if statement syntax is incorrect; it needs double brackets [[ ]] for numeric comparison.

D The script works correctly and will alert when usage is above 90%.

💡 Hint

Check how shell compares numbers inside single brackets.

The script correctly extracts the numeric disk usage and compares it with 90 using -gt inside single brackets, which works in POSIX shell.

🚀 Application

advanced

Automate disk cleanup to prevent outages

Which script snippet safely deletes only log files older than 30 days in /var/log to free disk space?

A rm /var/log/*.log -mtime +30

B find /var/log -type f -name '*.log' -mtime +30 -exec rm {} \;

C find /var/log -name '*.log' -delete

D find /var/log -type f -name '*.log' -mtime -30 -exec rm {} \;

💡 Hint

Use find with -mtime to select files older than 30 days.

Option B uses find to locate files ending with .log older than 30 days and deletes them safely. Other options either misuse rm or delete all logs regardless of age.

🧠 Conceptual

expert

How disk management strategies prevent outages in production

Which of the following best explains how disk management strategies prevent outages in production systems?

A By proactively monitoring disk usage, automating cleanup, and alerting admins, systems avoid crashes caused by full disks.

B By disabling all write operations when disk usage reaches 80%, preventing data loss.

C By automatically increasing disk size without human intervention to handle any load.

D By moving all data to RAM to avoid disk usage entirely.

💡 Hint

Think about practical, reliable ways to keep systems running smoothly.

Effective disk management includes monitoring, cleanup automation, and alerting to prevent full disks that cause outages. Other options are impractical or impossible.