hi.
Been running hassio on a 120gb SSD drive.
At some point I was unable to create backups and install addons etc. as the drive was out of space.
I decided to transplant the drive to my windows PC as this is where I feel most comfortable and there are no tools or hacks that will let you figure out what takes up the diskspace unless its the usual suspects like logging or DB history.
I did not succeed in enabling hassio debugging as this would allows me to start a SSH shell. But this is still a crude cmdline interface so I quickly gave up here.
So now I have the linux disk in my windows 10 box.
installed 2 tools:
- paragon extfs, trialware
- windirstats, freeware
the paragon tool will let you mount the linux drive in windows. supports read/write.
windirstats will give you a nice and quick overview of what folders are infact the culprit(s).
in this case the unify addon/container took almost 90 GB.
1000s of folders with the name tmp_repairDatabase
deleted those and placed the drive back into the hassio host.
booted it again and now we are back in business 
would be nice if one could see the disk consumption on the addons page.
I know we have CPU/RAM usage.
Hope this helps someone out there.