since a few weeks, I faced the same problem several times. All of a sudden, I get a system message like "0 bytes memory left on hard drive". Naturally, programs stop working normally and I can't save my files any more. But the weird thing is that I normally use only <10% of my hard drive memory.
So I run
> sudo du -x / | sort -n | tail
which shows that most memory (around 316 GB) is used in /var/lib/apt/lists/partial.
> cd /var/lib/apt/lists/partial && ls -lS | head
-rw-r--r-- 1 root root 323832110603 Jul 9 12:07 archive.canonical.com_ubuntu_dists_vivid_partner_binary-i386_Packages.bz2
-rw-r--r-- 1 root root 35325738 Apr 24 20:40 de.archive.ubuntu.com_ubuntu_dists_vivid_universe_binary-i386_Packages.bz2
-rw-r--r-- 1 root root 31033131 Apr 24 20:45 de.archive.ubuntu.com_ubuntu_dists_vivid_universe_source_Sources.bz2
-rw-r--r-- 1 root root 20363078 Apr 23 17:50 de.archive.ubuntu.com_ubuntu_dists_vivid_universe_i18n_Translation-en.bz2
-rw-r--r-- 1 root root 10157032 Okt 28 2014 de.archive.ubuntu.com_ubuntu_dists_vivid_universe_i18n_Translation-de.bz2
-rw-r--r-- 1 root root 8294644 Apr 24 20:39 de.archive.ubuntu.com_ubuntu_dists_vivid_main_binary-i386_Packages.bz2
-rw-r--r-- 1 root root 5114062 Apr 24 20:44 de.archive.ubuntu.com_ubuntu_dists_vivid_main_source_Sources.bz2
-rw-r--r-- 1 root root 4235430 Apr 23 17:50 de.archive.ubuntu.com_ubuntu_dists_vivid_main_i18n_Translation-en.bz2
-rw-r--r-- 1 root root 3456337 Okt 28 2014 de.archive.ubuntu.com_ubuntu_dists_vivid_main_i18n_Translation-de.bz2
Obviously there is one terribly large file archive.canonical.com_ubuntu_dists_vivid_partner_binary-i386_Packages.bz2.
I saw no other option but to delete this file manually. After that, everything worked fine. Since then, the same thing reoccurred 2 times about every two weeks.
Can anyone explain this strange behaviour, and what can I do about it?
Thanks in advance!
Regards, Juri