pfSense

Active vouchers are not written to the configuration file, after reboot/upgrade/powerfail can be re-used with an initial time.
/etc/rc.savevoucher is not marked executable, so that even minicron for storing vouchers is running, it is never launced.

But there is fatal bug in voucher_save_db_to_config() which causes pfsense crash due to an error in generated config.xml - active vouchers are named <0>, <1>,<2> etc. - not allowed in XML file.

Solution:

/* Save active and used voucher DB into XML config and write it to flash
 * Called during reboot -> system_reboot_cleanup() and minicron
 */
function voucher_save_db_to_config() {

    global $config, $g;

    if (!isset($config['voucher']['enable']) || $config['voucher']['saveinterval'] == 0)
        return;   // no vouchers or don't want to save DB's

    if (!is_subsystem_dirty('voucher'))
        return;     // nothing changed.

    $voucherlck = lock('voucher');

    // walk all active rolls and save runtime DB's to flash
    $a_roll = &$config['voucher']['roll'];
//    foreach ($a_roll as $rollent) {
    while (list($key, $value) = each($a_roll)) {
        $rollent = &$a_roll[$key];
        $roll = $rollent['number'];
        $bitmask = voucher_read_used_db($roll);
        $rollent['used'] = base64_encode($bitmask);
        $active_vouchers = voucher_read_active_db($roll);
        $db = array();
        $dbi = 1;
        foreach($active_vouchers as $voucher => $line) {
            list($timestamp,$minutes) = explode(",", $line);
            $activent['voucher'] = $voucher;
            $activent['timestamp'] = $timestamp;
            $activent['minutes'] = $minutes;
            $db['v' . sprintf("%03d", $dbi)] = $activent;  // write <v001>, <v002>, ...  instead of <0>, <1> (not allowed in XML file)
            $dbi++;
        }
        $rollent['active'] = $db;
    }
    clear_subsystem_dirty('voucher');
    unlock($voucherlck);
    write_config();
    return;
}

After this change it's safe to mark /etc/rc.savevoucher executable, config.xml is no more broken

Q: Is 1000 active vouchers per roll enough? If not, please replace sprintf("%03d",... with something else