FUELPHP Mongo TASK backup

mongo.php

<?php

namespace Fuel\Tasks;

class Mongo {
    
    public function run() {
        $file = \Fuel\Core\Config::load('db');
      	$env = $file['mongo']['default']['hostname'];
        exec('cd fuel/app/backup/ && mongodump --journal --host ' . $env . ' --port 27017 && tar -zcvf backup_'.date('Y-m-d-h-m-s').'.tar.gz dump && rm -rf dump;');
    }
}