Foundation concepts: Storage, Information lifecycle management, Power protection.
Definition: Secondary copies of data and applications kept to guard against catastrophic loss in the event of a system failure.
Not to be confused with:BackUPS, the trade name of a variety of uninterruptible power supply.
Hardware failures do occur. They can be made less common by using only the most reliable hardware components, employing all available power protection technologies, and regularly monitoring system performance to catch problems before they occur, but nothing can prevent unexpected failure.
When a computer system suffers a hardware failure, it will sometimes leave data stored on disks undamaged, but some failures can destroy a disk drive, and some will result in damage to files: if an application is actively modifying a data file when the computer suddenly stops working, the file can be left in an intermediate state with just half of the change made (perhaps a balance transfer had credited one account but not yet debited the other), leaving the file's state invalid.
Sadly, amongst the most common forms of hardware failures are failures of the disk system itself. Damage may range anywhere from a slight degradation in performance to a complete loss of all data and the disk itself becoming unusable.
Additionally, software problems are very likely to cause loss of data. The presence of Bugs in applications is extremely wide-spread, and, if an application is “buggy,” it could do anything from occasionally failing to update files completely to accidentally deleting everything stored on the disk.