I frequently find myself using Google as a substitute search engine over various sites' integrated searches, including CPAN. I just do a google on
my search terms site:whateversite.org. For example, in this case a google search for
log file site:cpan.org returns a few useful options near the top. IIRC, the second result
Log::Log4Perl is a fairly common option for logging in Perl.
This isn't a foolproof approach, but I favor it because Google will tend to rank pages which are frequently linked for your search terms higher than pages which aren't. The only drawback is that occasionally someone has named a module to match your search terms exactly, but through bad luck that module is actually either inappropriate, broken, not maintained, etc. Google will still rank it highly simply due to the exactness of the match to your search terms.