I'm running Kubuntu 20.10. I had at least some 5 GB free earlier today. Then apps started acting up. I checked in dolphin, and found I had 0 GB free. I cleared space, at least 2 GB, but it filled up again. My computer is going through the same cycle repeatedly, filling up the disk space after I clear it. I can't make out what files are being created, or how this is happening. I tried following advice from this site, such as using lsof to see if a particular process is the culprit, but that doesn't seem to be the case.
Because of the sudden nature of the problem, I fear some sort of malware.
I have tried putting ClamAV, but it gives error when attempting to download definitions.
Please advise. Thanking you in advance.
Edit: Apparently I can login to TTY. I tried this and deleted a file from TTY, but the space cleared starts filling up again immediately.
Now I'm running 'du -h --time / | sort -rh' in case that helps.
31 Answer
I'd start by checking /var/log for extensively large files.
Boot a Live-USB, mount your system volume (or the appropriate volume, where /var/log resides) and check file-sizes. If you find very large files in there, I'd suggest checking the contents with the tail command (eg. tail -n 100 /var/log/large_file, where -n 100 is the amount of lines of the end of the files to get output) to see whats going on in there, as opening in a normal editor may take a while and eventually fill your RAM.
If its not the log-files, another very useful tool is QDirStat: it shows how much space is in use by all the subdirs of a given starting directory. It's not installed by default, but should be in the universe repository, if I am not mistaken.
As an alternative to QDirStat, you can try du from a live-USB. Again, mount your affected system volume, then:sudo du -sh /mountpoint/of/your/system gives you a summary (-s) in human readable format (-h) of disk usage of your folders. From there you can manually iterate down the largest folders by repeating the command and adapting the given path.
