In message <slrndqkq5q.1on1.pino@mud.stack.nl>, Martijn van Buul writes:
>Hello.
>
>Last night, my laptop suddenly started yelling "Filesystem full on /usr",
>out of nowhere. I had been doing a massive rebuild, so my first assumption
>was that something had gone beserk, as I usually have around 12GB free.
>
>However, I was unable to find the culprit. 'df' claimed that the disk was
>105% full, all emergency blocks used, but 'du' could only account for about
>4G (It's a 16GB filesystem). So I rebooted to single-user mode, did an
>fsck -f, which didn't find anything, and presto: /usr is at 23% capacity 
>once again. 
>
>Any idea what might've gone wrong?

Deleted files which are still open take up disk space.

-s