Monitoring System Resources with top, htop, and vmstat

Tutorial Overview

This tutorial covers real-time monitoring of system resources using top, htop, and vmstat on a Debian-based Linux system. These tools help monitor CPU, memory, and process usage, providing valuable insights into system performance.

Prerequisites

Root or sudo access.

Steps

Step 1: Monitor System Resources with `top`

1. Open a terminal and run:

top

The top command provides a real-time view of system processes and resource usage.
Key columns include:
- PID: Process ID.
- USER: Owner of the process.
- %CPU: CPU usage percentage.
- %MEM: Memory usage percentage.
- TIME+: Total CPU time the task has used since it started.

2. Basic Navigation in top:

Press M to sort by memory usage.
Press P to sort by CPU usage.
Press K to kill a process by entering its PID.
Press Q to quit top.

Step 2: Install and Use htop for Enhanced Monitoring

1. Install htop:

sudo apt update
sudo apt install htop -y

2. Launch htop:

htop

htop offers a more user-friendly and interactive interface compared to top, with color-coded bars and mouse support.

3. Navigate and Manage Processes in htop:

Use the arrow keys to scroll through processes.
Press F6 to change sorting criteria.
Press F9 to kill a selected process, then choose the signal type.
Press F10 to quit htop.

Step 3: Monitor CPU, Memory, and Disk I/O with vmstat

1. Run vmstat to see an overview of system performance:

vmstat 5

This command updates every 5 seconds.
Key columns include:
- r: Number of processes waiting for CPU.
- b: Number of processes in uninterruptible sleep.
- swpd: Amount of virtual memory used.
- free: Free memory.
- si/so: Swap memory in/out.
- us/sy/id/wa: CPU utilization (user, system, idle, and I/O wait).

2. Capture Historical Data with vmstat:

To capture data over a period, use:

vmstat 2 10

This command takes snapshots every 2 seconds, 10 times in total, providing a longer view of system performance.

Monitoring and Performance