At the moment the disk usage pie chart displayed for Linux hosts isn't very useful if you're using LVM, as it just displays 100% used of an aggregate of all the devices - e.g. I have a new, unused desktop that has

1TB         /

8TB       /data

256Gb /scratch

and the inventory page will display 9.3 TB at 100% usage.

A useful output would to instead list the output of "df -h" excluding items matching udev, tempfs, /dev/loop - so for me this would be

/dev/mapper/ubuntu--vg-root            915G      8.1G      861G      1%      /

/dev/mapper/data--vg-data                  7.3T      93M      6.9T      1%      /data

/dev/mapper/scratch--vg-scratch      234G      61M      222G      1%      /scratch

etc.

This would allow monitoring of individual mountpoints which would be far more useful than just a total aggregate figure.