BBB No space left on device

I have a BBB that I wanted to use for a project openhab. I can not copy the necessary files (java + openhub). Wanted to do three questions: 1) it is possible to set an upper limit of occupation before the BBB does not freeze (resulting in the ssh service can not be reached)?
2) Which linux distro is the most agile and economical use of space (only use ssh no X and VNC)
3) E 'possible to lighten the distro by default? (erasing what?)

I installed ubuntu 12.04 last night onto my BBB with LXDE and It only uses 48% storage.

Dan Metcalf