About differential backups
Unlike the transaction log backup, the differential backup is a backup of the database. The differential includes all of the changes that were made since the last full backup. If you made several differential backups since the last full backup, you only need to restore the last full database, followed by the last differential. You would not need to restore any of the intermediate differentials.
Differential backups include the following types of backups:
Database differentials
Individual filegroup differentials
Read-write filegroup differentials, i.e., any backups that include differentials on all the read-write filegroups in a database.
Partial differential filegroups, i.e., any backups that include differentials of only the filegroups that the user selects.
Caution:
Microsoft recommends that you do not create more than one type of differential backup for the same object.
Caution:
NetBackup does not consider differential images when it determines recovery staging strategies if more than one type of differential is found for the same object.
A typical backup procedure may use full database, differential, and transaction log backups in ascending order of frequency. For example the full database backup may be taken bi-weekly and the differential may be taken nightly. Then the transaction log backup may be made more frequently for either mission critical or high volume applications.
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