Data Backup Systems

Data Backup Systems

An understanding of data backup systems is important for locating responsive electronic data. Three backup strategies are available to data administrators. The full backup, as the name implies, backs up all system data. However, even full backups do not commonly involve the backup of all data. Application files (such as the files which compromise Microsoft Word) are not usually backed up since they can be reinstalled using the application CDs. Instead, only configuration files and actual data files created by the users are backed up. A system restoration requires only the most recent full backup. However, full backups take the most time and media space. The differential backup saves files which have changed since the last full backup. The last full backup and the most recent differential backup are required to restore the system. The incremental backup saves only those files which have changed since the last incremental backup. It requires the least amount of backup time and space, but all incremental backups since the last full backup are required to restore the system. The size of the system may require that incremental backups be performed during the week and full backups on the weekend. The difference between the different types of backup strategies is illustrated below:

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