First, buy a big UPS. :)

The problem you are liable to run into is connectivity to the client browser. There are all sorts of reasons that the socket can break, including death of the browser, and these you can do nothing about, except be prepared to gracefully handle the error on your end.

It's also possible to emit an HTML page that refreshes itself every several seconds, re-invoking the CGI each time. This would leave you with less server-side error handling, though you might need to do something to cache a database handle. Tricks for doing that are available through mod_perl.