Data loss

Encyclopedia : D : DA : DAT : Data loss

In computing, data loss refers to the unforseen, usually accidental, loss of data or information. It can happen due to several reasons:

Power failure, resulting in data in volatile memory not being saved to permanent memory.
Hardware failure, such as a head crash in a hard disk.
A software crash or freeze, resulting in data not being saved.
Software bugs or poor usability, such as not confirming a file delete command.
Data corruption, such as filesystem corruption or database corruption.
A malicious act, such as a worm, virus, hacker or theft of physical media.
A human error, such as accidental file deletion.

or a combination of more than one of the above.

Studies have consistently shown hardware failure and human error to be two most common causes of data loss, accounting for roughly three quarters of all incidents.

One other cause, commonly overlooked, is natural disasters. Although the probability is small, the only way prevent data loss due to natural disasters is to store backup data in a physically separate location.

Data loss must be distinguished from data unavailability, such as may arise from a network failure, although the two have substantially similar effects.

Preventing data loss

There is no guaranteed way to prevent data loss; however, the frequency and impact of data loss can be greatly mitigated by taking proper precautions such as: backup power supply, regular data backups, journaling filesystems, redundant storage (such as RAID), antivirus and firewalls, regular installation of security fixes and user education.

Data recovery

Main article: data recovery

Lost data can often be recovered. There are commercial services that attempt recover data from physically damaged media. Filesystem corruption can usually be reparied by the user or the system administrator with the right software tools. A deleted file is rarely overwritten on disk; it is more usual for the operating system to simply delete its entry in the filesystem index. This can be easily reversed.

References

Graziadio business report - [The cost of lost data]

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