By the "old books" one should divide the root fs in several parts, which is totally meaningless on most normal Ubuntu machines, but which makes sense when using quota.
One of the common cases when quota is offended is that some application does not clean up after itself in the /tmp directory. A recommendation would therefore be to partition the system so that either the following is true (on different partitions):
- "/home" + "/"
- "/" + "/tmp"
- "/" + "/home" + "/tmp"
- "/" + "/home" + "/tmp" +"/usr"
Either of the first two is however a very good idea. The main point is to separate /home from the rest and have it either on a fs of it's own, or together with the root-fs but then having /tmp separated instead (since users usually don't have write access anywhere else). The second one actually makes more sense and is the one prefered by me. The reason is that /bin and /usr today aren't considered big relatively speaking and since it would allow the most important of your drives (the one containing /home) to be easilly movable and bootable on another HW.
The second case also happens to be the easiest way to fix a monolithic system withou tinkering with the main drive (re-partitioning is always a operation that would make me shit in my pants ;) ). Just find one of your old discontinued drives, add it to the system and mount it as /tmp and you're done.
In case you're out of luck and you don't wish to reinstall the whole server (at least not now), the following command might come in handy:
sudo find / -user $AUSER
