What does a differential backup do?

A differential backup is designed to save only the files that have changed since the last full backup was performed. This means that, when you execute a differential backup, the system compares the current files with those stored in the last full backup. It identifies and backs up only those files that have been modified or added after that full backup.

This method is efficient because it reduces the amount of data being processed and stored compared to a full backup, which captures everything, regardless of whether files have changed or not. It provides a balance between backup speed and the amount of data that must be restored in the event of a data loss scenario.

This approach contrasts with other backup strategies, such as incremental backups, which back up only the files that have changed since the last backup of any type, and full backups, which save everything. Consequently, differential backups facilitate quicker recovery while requiring less storage space than full backups.