Which method of backup increases the risk of data loss if the last full backup is damaged?

• A. Full backup
• B. Incremental backup
• C. Differential backup
• D. Mirror backup

Answer: (B)

The correct answer is incremental backup because this method involves backing up only the data that has changed since the last backup. Consequently, if the last full backup becomes damaged or corrupted, and one relies solely on incremental backups, there is a potential risk of losing all the changes made since that last full backup. Each incremental backup is dependent on the full backup, so the loss of the full backup effectively means that all subsequent incremental backups cannot be restored independently.

In contrast, a full backup captures all data at a single point in time and does not depend on any previous backups, which means if it is preserved, recovery is straightforward. A differential backup includes all changes made since the last full backup, allowing for easier restoration compared to incremental backups, as only the last full backup and the most recent differential backup are necessary for recovery. A mirror backup creates an exact copy of the data at the time of the backup, which does not rely on previous backups and therefore does not face the same risk if the last full backup is damaged.