I don't think gregor42 meant that your question was off topic... As I read it, the answer was marked as off-topic. (i.e. not really perl related) In the same spirit my answer below is probably off topic as well....

In my experience, scripts that automatically diagnose and "fix" a problem (ala bouncing your webserver) are more trouble than they are worth. I'd recommend running a full fledged monitoring program that alerts you whenever a problem occurs. I've had good success with Big Brother but am seriously considering switching over to netsaint. Both systems religiously monitor everything from memory usage, to internet connectivity, to database connectability (sp?). You can also write your own "plug-in" scripts to monitor anything you want. Some have even used this feature to send out stock market alerts, or keep an eye out for cheap airline tickets.

While the last two uses are rather esoteric, having a monitoring system that is easily customizable, is crucial to running a high quality internet service.

-Blake