Certified Information Systems Security Professional (CISSP) Practice Exam 2026 – All-in-One Guide to Mastering Your Certification!

A differential backup is the method that results in storing only files that have changed since the last full backup. This type of backup captures all changes made since the last full backup, allowing for more efficient storage and quicker restoration than a full backup, as it combines the ease of recovery seen in full backups with the efficiency of not needing to back up every single file each time.

In a system utilizing differential backups, each subsequent differential backup after a full backup includes all changes made since that original full back up. This means if you performed a full backup on Day 1 and then two differential backups on Day 2 and Day 3, the Day 2 backup would include all changes from Day 1, and the Day 3 backup would include all changes from Day 1 and Day 2. To restore data, you would only need the last full backup and the latest differential backup, making the process straightforward and reducing recovery time.

While incremental backups also contribute to efficient storage by only backing up files that have changed, they differ because they only capture changes made since the last backup of any kind (either full or incremental). This means that restoring from incremental backups can be more complex, as multiple backup sets are needed for a complete restoration.

Mirrored backups