I have a multi drive set up with home and swap split off to separate HHDs and everything else on my SSD (30GB partition, ~19gb free).
Whenever I go to compress a large folder on a USB external drive to the same location (the external drive) using the GUI right click 'Compress...' option and then selecting the .7z radio button, I see the free space in root slowing drop till it gets to about 200mb and the compression fails. It looks like the file is being written into root as well as onto the external drive for some reason.
I have been trying to identify the file which is filling up but have been unable to narrow it down and cant work out why my root directory is even being writ too... I saw in another post to use
sudo du -ax / | sort -nr | less -S which i have piped into two txt files for before compressing and around half way through compressing which i can provide but are massive and i cant see any differences big enough to explain it. I have also looked at var/log files but cant see anything filling up there.
Sorry this is my first time using Linux full time and been looking at this for 2 days with no progress. Is this a known thing? or do i have something set up wrong as i cant understand why its writing to root.
EDIT: Ubuntu 18.04 Yes but ideally i would rather it not use any internal drives for copying data on an external drive to an external drive.