User:Austinmurphy/Data loss

Data loss
Loss of Data can be costly to individuals and oraganizations. A backup and recovery strategy is designed to minimize the cost of such an event.

Types of Data Loss
A Data Loss Event is any event that leaves the user of a computer system without data that was previously available and is now desired. This can be any event such as:
 * Intentional Actions
 * Intentional deletion of a file or program
 * Unintentional Actions
 * Misplacement of CDs or floppies
 * Administration errors
 * Failure
 * Data corruption due to system or program bugs
 * Physical failure (eg. dead disk, scratched CD-ROM, power surge)
 * Disaster
 * Fire, earthquake, flood, tornado, etc.
 * Crime
 * Theft, hacking, sabotage, etc.

Cost of Data Loss
The cost of a Data Loss Event is directly related to the value of the data and the length of time that it is needed, but unavailable. Consider:
 * The cost of continuing without the data.
 * The cost of recreating the data.

Recoverability from Data Loss
Successful recovery from a Data Loss Event generally requires an effective backup strategy. Without a backup strategy, recovery requires reinstallation of programs and regeneration of data. Even with an effective backup strategy, restoring a system to the precise state it was in prior to the Data Loss Event is extremely difficult. Some level of compromise between granularity of recoverability and cost is necessary. Furthermore, a Data Loss Event may not be immediately apparent. An effective backup strategy must also consider the cost of maintaining the ability to recover lost data for long periods of time.

The most convenient backup system would have duplicate copies of every file and program that were immediately accessible whenever a Data Loss Event was noticed. However, in most situations, there is a correlation between the value of the data and the time it takes to notice there has been a data loss event. Taking this into consideration, many backup strategies decrease the granularity of restorability as the time increases since the potential Data Loss Event. By this logic, recovery from recent Data Loss Events is easier and more complete than recovery from Data Loss Events that happened further in the past.

Recovery is also related to the type of Data Loss Event. Recovering a single lost file is going to be substantially different than recovering a whole system that was destroyed in a flood. An effective backup regimen will have some proportionality between the magnitude of Data Loss and the magnitude of effort required to recover. For example, it should be far easier to restore the single lost file than to recover the whole system destroyed in a flood.