Linux health monitoring

[James Sissel]

We here at work are at the mercy of the Linux
Administrators to do their jobs.  Since they can't
seem to do this and our /var partition ran out of
space Friday our Oracle Applications crashed.  It
looks like we will have to monitor the health of our
RH Enterprise 2.x server to make sure this doesn't
happen again.  Is there any good piece of free open
source software that does such a job?

Thanks