This class is quick and simple to install into any PHP application, and is easy to customise to the display you require.
The script finds the amount of total disk space on your system, and then the total free space. We then calculate the used space and give it to you as a percentage.
This class was developed by Fred Bradley - http://twitter.com/fredbradley
You can choose the path of the disk that you want to check (if you have multiple disks mounted, for example). You can do this by setting the first paramater when calling calling the Class to the directory that you want to check. EG: $disk = new DiskSpaceCheck('/var/www/vhosts/');