Historically, backups have been used to protect against or recover from a data loss. Backups are made by copying data to secondary media using different backup techniques at a specified time. With events like September 11th and the recent historical power failure in the Northeast, companies are beginning to realize that backups are no longer used just to restore data in cases of crisis, but also in cases of software corruption, human error, hardware failure, or in order to recover older versions of a file. Consequently, enterprise consciousness surrounding disasters has significantly risen, and it has become increasingly clear that disasters of unfathomable sizes can occur at any given time. Therefore, companies must be prepared for the worst. These myriad events have launched a high anxiety over data protection and recovery among IT professionals across the globe, in particular among Database Administrators (DBA). This concern is highly warranted according to the National Archives and Records Administration; "ninety-three percent of companies that lost their data center for ten days or more due to a disaster file for bankruptcy within one year of the disaster" (Wood, Part 1). .
Not only are Database Administrators concerned with the overwhelming need for effective backups, but also with how quickly and efficiently the data can be backed up and recovered. Unfortunately, data is being generated with increasing frequency and volume, and the timeliness and efficiency of backup and recovery are decreasing disproportionately. Therefore, DBA's must explore different means of backup in order to stay abreast with the exponential growth of data. The idea of preventing against loss of data and doing so in a timely manner has raised one question: What approaches to backup and recovery should be taken? Two alternatives are alive today: tape and disk backups. However, in order to determine the most appropriate means of backup, the principle of backups must be understood, and both past and current methods must be explored.
