When backing up data, a company has a few different ways to back the data up, depending on time requirements during the backup or restore process. When a company is planning its backup and restore strategies, it must decide whether it wants a quick backup and slower restore or a slower backup and faster restore. This decision then determines which backup type is most beneficial to the company.
A full backup is performed by small organizations that have less data to back up or larger corporations that can afford faster backup equipment. A full backup consists of copying all files to a backup device. When the full backup is done, each file backed up will have its Archive attribute turned off.
Note: The Archive attribute is a setting on each file that shows whether the file has been modified. When a file is created or modified, the Archive attribute is turned on. When some backup types are performed, files with the Archive attribute are backed up and then the attribute is turned back off. This allows only changed and new files to be backed up.
An incremental backup backs up files that have changed since they were last backed up or those with the Archive attribute turned on. Once a file is backed up, its Archive attribute is turned off, so it will not be backed up again unless it is changed or a full backup is performed.
A differential backup is almost the same as an incremental backup, except when a file is backed up, the Archive attribute is not turned off. Leaving the Archive attribute on means that the file will be backed up again, regardless of whether the file has changed after the last differential backup. This basically means that all files that have changed since the last full backup will be backed up during the differential backup.
A copy backup is where all files are backed up, but the Archive attribute is not changed. A copy backup is the same as a full backup, but it does not change the Archive attribute. This lets the administrator back up all files without causing a change in the regular backup schedule.
[tags]diana huggins,data protection,disaster planning & recovery,data loss,backup plan[/tags]