SQL Server Interview Question #188

What is a differential backup?

Security, Backup, Recovery, Administration & Real-World Scenarios Senior Advanced

Detailed Explanation

A differential backup contains data extents changed since the most recent full database backup that serves as its differential base.

To restore using differentials, restore the appropriate full backup and then the latest required differential backup. Differential backups generally become larger as more data changes after the full backup, until a new full backup resets the differential base.

Code Example

BACKUP DATABASE SalesDb
TO DISK = 'D:\SqlBackups\SalesDb_Diff.bak'
WITH DIFFERENTIAL, CHECKSUM, COMPRESSION;