I have a server monitoring page I built. It tells me the status of several server operations. It shows CPU, disk usage...etc. Right now I just have it showing if MySQL is up or not by looking at mysqladmin status Threads. I would guess that as long as there is one thread present the MySQL server is up?

I would like to add the ability to tell if MySQL is overloaded or at what level it is running (approx). What ssh command could I derive this information from? What information should I be looking for?

Is there a metric available that would tell me the 'load' on MySQL at any given moment?

(on a Linux box running apache php mysql)

Thanks in advance for any guidance or assistance you may be able to provide.