I use:

use Storable;
$global_config = retrieve('/path/to/my/config.sto');
[download]

in my scripts, that way I can access things like $global_config{'logdir'} globally. I have another script which can add/change/delete hash entries and then nstore \%global_config, '/path/to/my/config.sto'; them.
It seems to load up very quickly and has worked very well for me in the past.

-Waswas