Check if a web server is down

Hello all,
I'm working on an 'alert' mechanism which would send a mail to the
admins
if the web server is down. I plan to do this in Perl's LWP.

Along these lines,
================================================== ================
use LWP::Simple ;
my $chkUrl = get("http://abc.xyz.com");
if ( ! $chkUrl )
{
&mail_the_Admins_the_server_is_down() ;
die "Cant connect: Check if the server is down\n" ;
} else { &do_some_prcessing_here() ;
}
================================================== ================

I expect this piece of code to be used over and over in our services
and want to minimize performance hits that the web server takes on
each check.

Could anyone recommend the best way to check for web server being up
or down without causing major performance issues, please?

Should I use a HEAD request for an URL on the server?
I dont want the script to keep pinging the server.

Thanks for your time,
Lax