I have a 120GB SSD and a 250GB HDD on my system. The operating system is on the SSD, the HDD for 3 folders - Pictures, Music, Manuals. The HDD died. Syslog viewer kept coming up with hundreds of errors. I kept trying to access the HDD, hoping it might repair itself. Yeah, sure!. Gave up, and pulled the drive. System worked fine, but every time I tried to save a file to the SSD, the system would tell me that the drive was full. Normally, the file system consumed about 35GB. Huh!
Looked everywhere. Could not find where all those files were. Then, I found a folder called "timeshift". I don't have "timeshift" in my system menu. I looked into "timeshift" and found that it takes a photo of the system every time something in the system changes and stores it in a folder called "snap". Well, snap was 76GB. AHA!
Every time the HDD started throwing errors, timeshift would make another "photo" and put it in the "snap" folder. Hence, after a while it filled the whole SSD up.
Erased "timeshift" and "snap". Now the system works great! Can save files and update stuff. Need a new HDD, and I have backups to fill it. No problem.

2 caveats: If you have "timeshift" don't keep trying to access a bad drive. You'll just keep making the "snap" folder bigger and bigger. Second, when troubleshooting a system do it as the su (root). I missed a bunch of stuff. Mainly the size of the "snap" folder.

Art

I think it might be better said, if you use timeshift, configure it properly. And I don't know what that second caveat is all about.

But all in all you did pretty good. Thanks for sharing!

During backups i check which files are moved.

cp -avr ...

Just sit and watch. Those files and directories which takes longer have usually the lint. It pays off to watch it and do backups regularly.

in regards of the hidden issue in your topic:

http://www.marzocca.net/linux/baobab...aobab-fullscan

Baobab is a nice graphical tool to find directories which are huge.