The need to provide reliable data availability has always driven data center design. Redundant storage systems and backup mechanisms are essential for enterprises to provide 24/7 data access. Using a redundant array of independent disks (RAID) and data server clusters helps prevent catastrophic data loss. However, redundancy within the data center itself represents only a partial solution. Although backup mechanisms preserve data, you have a high-availability solution only if redundancy also protects against a network failure between the center and the outside world. A distributed data center provides such a solution.