Have you considered using the built-in (with Unix) DBM flat-file database method? This allows you to store hashes in a file and would greatly increase the access speed to your data. If you have "Learning Perl" or "Perl Cookbook", read up on this topic. I think it's exactly what you are looking for.

$PM = "Perl Monk's";
$MCF = "Most Clueless Friar Abbot";
$nysus = $PM . $MCF;