The configuration of the live site will be dictated by a number of factors — the functionality of the site plus the expected traffic. Quite often a site can be divided into several parts, which are best handled on different machines. One might handle data-intensive actions — serving a large stock of images for instance. Another might be concerned with computations and a database, while a third might handle secure access. They might be replicated for backup and maybe mirrored in another continent to minimize long-haul web traffic and improve client access. Load sharing and automatic-backup software will be an issue here (see later).