Knowing how your server uses CPU, memory, disk, and network resources is essential for capacity planning and troubleshooting. Ubuntu 26.04 LTS comes with several built-in tools and supports popular third-party monitors. This guide covers the most useful commands and tools for resource monitoring.

Tested and valid on:

  • Ubuntu 26.04 LTS

Prerequisites

  • Ubuntu 26.04 LTS server
  • A user with sudo privileges

Step 1 – Quick Overview with top

The built-in top command shows real-time CPU and memory usage:

top

Press q to exit. Sort by CPU with P or by memory with M.

Step 2 – Install and Use htop

htop is an improved interactive process viewer:

sudo apt install htop -y
htop

Use arrow keys to navigate, F9 to kill a process, and q to quit.

Step 3 – Check Memory Usage

Get a quick memory and swap summary:

free -h

Detailed virtual memory statistics:

vmstat 1 5

Step 4 – Check Disk Usage

Show disk space used by all mounted file systems:

df -h

Find which directories use the most space:

du -sh /var/* 2>/dev/null | sort -rh | head -10

Step 5 – Check Disk I/O with iostat

Install the sysstat package for iostat:

sudo apt install sysstat -y
iostat -xz 1 5

Step 6 – Check Network Traffic

Install and use nload for real-time bandwidth monitoring:

sudo apt install nload -y
nload

Or use ss to list active connections:

ss -tuln

Step 7 – Install Glances (all-in-one dashboard)

glances provides a comprehensive dashboard in one screen:

sudo apt install glances -y
glances

Step 8 – System Load and Uptime

Check system uptime and load average:

uptime

View detailed system information:

uname -a
lscpu | grep -E 'CPU|Thread|Core|Socket'

Conclusion

You now have a toolkit of monitoring commands and tools for Ubuntu 26.04 LTS. For persistent monitoring with alerting and historical graphs, consider deploying Prometheus with Grafana or installing Netdata — both covered in later tutorials in this series.