If a system goes down, there may be data loss. Data can either be restored from backup or by switching over to another system to which data has been replicated. It is vital that the integrity of the data be checked before user access is re-enabled. If the data is corrupt or the database system is not working properly, trying to add more data to it could result in even more severe problem

In a large-scale disaster, numerous systems that the company depends upon could fail. After a disaster, resources are likely to be scarce and time pressures severe. Consequently, disaster recovery plans should identify priorities for restoring particular systems first. This process has to be conditioned by dependencies between different systems. The servers running the website front-end might not be able to operate effectively if the servers running the database are not available.

Business continuity and contingency plans put systems and working methods in place to be resilient to failure. Disaster recovery has a different emphasis; it creates workflows and resources to use when a specific disaster scenario affects the organization. A disaster could be anything from a loss of power or failure of a minor component to man-made or natural disasters, such as fires, earthquakes, or acts of terrorism. For each high-risk scenario, the organization should develop a plan identifying tasks, resources, and responsibilities for responding to the disaster.

To help protect against losing access to a computer system when a component fails, you must implement fault tolerance. Fault tolerant systems are those that contain additional components to help avoid single points of failure. Business continuity plans will start with analysis of business processes and assets to identify critical workflows and resources plus vulnerabilities in those systems. These vulnerabilities can be mitigated by creating contingency plans and resources that allow the system to be resilient to failures and unexpected outages. Most contingency plans depend on providing redundancy at both the component and system level. If a component or system is not available, redundancy means that the service can failover to the backup either seamlessly or with minimum interruption.

Most organizations are reliant to a greater or lesser extent on the availability of their apps and data to continue trading. Many are also reliant on the continued availability of services, such as cloud storage or apps, that are used within their organization. Without continuous access to these data and apps, whether held on-premises or in the cloud, organizations cannot function properly. There can be a significant cost implication for an organization during an outage. Consequently, it is important that you understand possible risks and common mitigations.