This planning Guide helps database designers and systems engineers design data centers that can achieve the level of availability needed for particular business environments. This guide discusses each barrier to achieving a highly available datacenter and analyzes the solutions to each of these barriers. The importance of using a combination of best practices, database backups, redundant components, and redundant servers is emphasized as the key to ensuring high availability. This guide covers: Best practices to prevent downtime; Using backup to recover from disaster; Using hardware redundancy to prevent downtime; Using redundancy to minimize downtime.