What Does Differential Backup Mean?
Differential backup is a data backup procedure that records data changes that have occurred since the most recent full backup. Differential backup only saves the new data or data that has changed since the last full backup; it does not make a backup of all the data every single time. The benefit of using differential backup, versus a full or incremental backup, is that it takes a relatively shorter amount of time to restore the data. However, if done several times without occasionally performing a full backup, the size of the differential backup can grow larger than the baseline full backup.
Techopedia Explains Differential Backup
It involves less storage drive space than incremental backups.
The amount of time for backup is much quicker than full or incremental backups.
Restoring files may take longer since it may have to be done from both the full and differential backup.
Restoring individual files might take a while since it has to be searched from either the full or differential backup.