Install xfce4-fsguard-plugin by entering the following commands in the terminal:
sudo apt update sudo apt install xfce4-fsguard-plugin
Description:
filesystem monitor plugin for the Xfce4 panel
The fsguard plugin checks free space on a chosen mount point frequently and displays an alarm if free space is less than given alarm limit.
Homepage: http://goodies.xfce.org/projects/panel-plugins/xfce4-fsguard-plugin
Version: 1.1.0-1
Section: universe/x11