Business continuity is a wide-ranging subject that analyzes all aspects of how a business maintains service to its customers when faced with an unexpected disaster. When creating a business continuity plan, companies must trade off the cost of the additional required infrastructure such as hardware, software, telecommunications, and buildings, against the risks, such as the costs of a prolonged outage. As a result, systems that are critical to the business and those for which there is a legal requirement are the top priorities.
For a service to be available, all the constituent pieces must also be available. The key issue is rapid recovery of individual service elements. Outages can occur from hardware failure such as component or power failures, or from software failures such as operating system panics and application crashes. Network connectivity failures can also affect service availability. Most of these failures can be masked through component redundancy or by having a standby server ready to take over the workload. The Geographic Edition framework is a building block for disaster tolerance which provides a framework that enables data services to be moved between a primary cluster and a geographically separated secondary cluster in a controlled fashion.