What Is Differential Backup?
A differential backup captures all data that has changed since the most recent full backup, creating a cumulative record of modifications until the next full backup is performed.
Unlike incremental backups, which track only changes since the previous backup operation, differential backups capture all changes made since the last full backup during every backup operation. As a result, each differential backup grows larger until a new full backup establishes a fresh baseline.
For example, if a full backup is completed on Sunday, every subsequent differential backup contains all changes made after that backup. Each new differential recovery point therefore includes both recent modifications and those captured in earlier differential backups from the same cycle.
This design simplifies recovery because restoration typically requires only two backup sets: the most recent full backup and the latest differential backup. Many organizations favor this approach when recovery speed is a higher priority than maximizing storage efficiency.
The tradeoff is capacity growth over time. Differential backups become larger as additional changes accumulate, which can increase storage consumption and backup duration before the next scheduled full backup resets the process.
Many enterprise platforms support combinations of differential, incremental, and synthetic full backups, allowing organizations to align backup methods with workload characteristics and recovery requirements.
Why Differential Backup Matters
Differential backups offer a balance between recovery simplicity and storage efficiency. They reduce dependency on long backup chains while avoiding the resource demands associated with frequent full backups.