Common Causes of Data Loss

There is no single most effective way in which to ensure data is protected. The approach to backups and restores depends not only on the organization’s computer and networking resources, but also on the cause and, therefore, the extent of data loss.

The following are the most common causes of data loss.

1. User Error
2. Data Corruption
3. Hardware Failure
4. Disaster

User Error:- Users most frequently experience data loss limited to one or a few files, usually caused by deleting or overwriting files. If a user’s data is only on the local computer and is not backed up, there is no alternative other than to recreate the data. If the data is on a server, a backup may contain an earlier version of the file, which can be restored. (Mirroring data to another disk is not an effective solution for this problem, since the user’s error will also be replicated.) Unfortunately, locating and restoring single files from a tape backup is a time-consuming and costly process.

Data Corruption:- Software bugs or virus attacks can be limited to corruption of one or a few files, or can affect an entire application and its associated files. Regardless, recovery from this type of data loss requires restoring data and the application from a point in time before the problem. (As before, this precludes mirroring between disks as an option.)

Hardware Failure:- Hardware components (cables, power supplies, system boards, and disk drives) are all susceptible to failure. While some hardware losses simply render the data inaccessible, a disk failure can result in the loss of large amounts of critical data. (Similarly, notebooks are at high risk for complete data loss if stolen.) This type of data can be protected through hardware redundancy and mirroring, a method that not only has the advantage of keeping data available (since failover to the mirrored disk is automatic), but also up-to-date (since the mirrored disks remain synchronized until the point of failure). The disadvantages to this approach are the higher costs associated with hardware replication, as well as greater system administration complexity. For small and midsize organizations, the more common solution is to rely on tape backups and full restores of the disk’s data.

Disaster:- Although rare, losing a site to natural or man-made disaster is nevertheless a measurable risk. In the event of a site disaster, tape backups can provide the most effective means to restore data. Alternatively, if the capabilities exist, remote site replication of data is also an effective means of protection. 

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