Getting server CPU usage, memory left and disk space left on disk

Hi

I'm trying to detect when the memory on my server becomes to low, the cpu usage when it gets to high and when the disk space left on my server gets to low. Does anyone know how to do that with php?


Thanks

This might help a little: http://uk.php.net/manual/en/function.disk-free-space.php

HTH
Dan

Thanks now all i need is cpu usage left and total available memory left