What is a full data backup primarily used for?

A full data backup is primarily used to create a complete copy of all the data on a system or storage device. This type of backup captures every file, folder, and setting, ensuring that all information is preserved in the event of data loss due to hardware failure, accidental deletion, or other issues.

In the context of the choices provided, the correct answer aligns with the understanding that a full backup is aimed at creating a comprehensive archive of data rather than selectively copying files, compressing them, or impacting system performance. Full backups facilitate recovery processes where the entire dataset is reinstated as needed. This ensures that no critical information is missed and provides peace of mind by maintaining an extensive duplicate.

The other choices do not accurately represent the primary function of a full backup. For instance, compressing files can be part of a backup strategy but is not the primary objective of a full backup. Similarly, creating a mirror image pertains more to disk imaging rather than a standard data backup, and enhancing system performance is generally related to procedures like disk cleanup or optimization rather than the act of backing up data.