Which of the following backup techniques uses the least amount of space on the backup medium?

Which of the following backup techniques uses the least amount of space on the backup medium?

• Mirror backup
• Incremental backup
• Differential backup
• Full backup 

 

 

EXPLANATION

Incremental backup

An incremental backup is one in which successive copies of the data contain only that portion that has changed since the preceding backup copy was made. When a full recovery is needed, the restoration process would need the last full backup plus all the incremental backups until the point of restoration. Incremental backups are often desirable as they reduce storage space usage, and are quicker to perform than differential backups.

A differential backup is a type of data backup that preserves data, saving only the difference in the data since the last full backup. The rationale in this is that, since changes to data are generally few compared to the entire amount of data in the data repository, the amount of time required to complete the backup will be smaller than if a full backup was performed every time that the organization or data owner wishes to back up changes since the last full backup. Another advantage, at least as compared to the incremental backup method of data backup, is that at data restoration time, at most two backup media are ever needed to restore all the data. This simplifies data restores as well as increases the likelihood of shortening data restoration time.