i don't know about Catalyst, but basically there are many ways of storing data between processes. the most performant solution would lie in using shared memory. you create the shmem segment in the startup.pl of your application, and any of the app's pages store the common data on it and read from there.
for instance startup.pl might look like (assuming all of the application's global data are stored in a hashtable called %appdata):

use IPC::Shareable ':lock';
[...]
no warnings 'untie';
my $knot;
my $glue = "SHMEMGLUE";
eval { $knot = tie %tie, 'IPC::Shareable', $appdata{$glue}, { create =
+> 0, mode => 0666, size => $appdata{SHMEMSIZE},
                                                             exclusive
+ => 0, destroy => 0 };
        };
unless ($@) {
   $knot->remove;
   untie %tie;
   undef $knot;
}
$knot = tie %tie, 'IPC::Shareable', $appdata{$glue}, { create => 1, mo
+de => 0666, size => $appdata{SHMEMSIZE},
                                                          exclusive =>
+ 0, destroy => 0 };
untie %tie;
[download]

note: this code first tries to find the shmem segment, and if it exists it destroys it. this prevents you from allocating additional memory with each restart of apache.