When is a SQL server differential backup required?

  • A relatively small portion of the data in the database has changed since the last database backup. Differential database backups are most efficient if the same data is modified frequently.
  • You are using the Simple Recovery model, which does not permit Transaction log backups, and you want to perform backups more frequently than is practical for full database backups.
  • You are using the Full or Bulk-Logged Recovery model and want to minimize the time it takes to roll forward Transaction log backups when restoring a database.