How to Check Disk Usage on Your Dedicated Server

How to Check Disk Usage on Your Dedicated Server

Monitoring disk usage on your server is essential for maintaining its health and ensuring that your applications run smoothly. If your disk space is running low, it could lead to performance issues or even cause your applications to crash. In this guide, we’ll show you how to check disk usage on your dedicated server to keep everything in top condition.

Step 1: Access Your Dedicated Server

To check disk usage, you first need to log into your dedicated server via SSH (Secure Shell).

• Open your terminal or SSH client.

• Log in to your server by running the following command:

  • ssh username@your-server-ip

  Replace username with your server’s user account and your-server-ip with the IP address of your server.

• Enter your password when prompted.

Step 2: Use the df Command to Check Disk Usage

Once logged in, you can use the df command to check disk space on your server. This command provides a summary of disk usage for all mounted filesystems.

• Run the df command:

  • df -h

  The -h flag stands for "human-readable" format, which shows the disk space in a more understandable format (KB, MB, GB, etc.).

• Review the output: The output will look like this:

  Filesystem      Size  Used Avail Use% Mounted on
  /dev/sda1        50G   20G   30G  40% /
  /dev/sdb1       100G   45G   55G  45% /data
  

  Here’s what each column means:

  • Filesystem: The name of the disk partition.
  • Size: The total disk size.
  • Used: The amount of disk space that’s already used.
  • Avail: The available disk space.
  • Use%: The percentage of disk space used.
  • Mounted on: The directory where the disk is mounted.

Step 3: Check Disk Usage for Specific Directories

If you need more detailed information about which directories are consuming the most disk space, you can use the du command.

• Run the du command to see disk usage for a specific directory:

  • du -sh /path/to/directory

  Replace /path/to/directory with the path of the directory you want to check.

  The -s flag gives you the summary of the disk usage for the entire directory, while the -h flag makes the output human-readable.

• Example:

  • du -sh /var/www

  Output:

  5.6G    /var/www
  

  This shows that the /var/www directory is using 5.6 GB of disk space.

Step 4: Use ncdu for a More Interactive View (Optional)

For a more interactive way to explore disk usage, you can use the ncdu (NCurses Disk Usage) command. This tool provides a visual, navigable representation of disk usage.

• Install ncdu:

  • For Ubuntu/Debian:
    • sudo apt install ncdu
  • For CentOS/RHEL:
    • sudo yum install ncdu

• Run ncdu:

  • ncdu /path/to/directory

  Replace /path/to/directory with the directory you want to analyze, or simply run ncdu to analyze the root directory.

  Use the arrow keys to navigate and explore which files or directories are consuming the most space.

Step 5: Set Up Disk Space Alerts (Optional)

To prevent your server from running out of disk space, consider setting up alerts to notify you when disk usage exceeds a certain threshold.

• Install the monit monitoring tool:
• For Ubuntu/Debian:
  • sudo apt install monit
• For CentOS/RHEL:
  • sudo yum install monit

• Configure monit to monitor disk usage:

  • Edit the monit configuration file:

    • sudo nano /etc/monit/monitrc

  • Add the following to monitor disk usage:

    check filesystem root with path /
      if space usage > 90% then alert
    

  • This configuration sends an alert when disk usage exceeds 90%.

• Restart monit to apply changes:

  • sudo service monit restart

Step 6: Clean Up Unnecessary Files

If you notice that disk usage is too high, you can clean up unnecessary files to free up space.

• Clean up old logs:

  • Check the /var/log directory for old log files and remove them if they are no longer needed.
    • sudo rm /var/log/*.log

• Remove unused packages:

  • For Ubuntu/Debian:
    • sudo apt autoremove
  • For CentOS/RHEL:
    • sudo yum autoremove

• Delete unnecessary backups or other large files that are no longer required.

Conclusion

Regularly checking your disk usage is vital for maintaining a healthy server environment. By following the steps in this guide, you can monitor your server’s disk space and avoid any performance or stability issues caused by running out of disk space. Use tools like df, du, and ncdu to keep track of disk usage and take action when necessary to keep your server running smoothly.