gistfile1.pl

#!/usr/bin/perl

use strict;
use warnings;

use Parallel::ForkManager;

my $pm = Parallel::ForkManager->new(8);
for my $file (glob "/usr/local/backup/*") {
    my $pid = $pm->start and next;

    print "Attempting to copy $file\n";
    system("/usr/local/bin/rsync --progress --modify-window=1 -ruivtO /usr/local/backup/$file /remotedisk/disk1/");

    $pm->finish;
}

$pm->wait_all_children;