Converting differential backups to full backups
The agent checks to determine if a full backup exists for each database. If no previous full backup exists, a differential backup is converted to a full. For batch file-based policies, you can enable this behavior with the keyword CONVERTBACKUP.
The differential backup is converted as follows:
If you select a database for a differential backup, the backup is converted to a full database backup.
(Intelligent policies) If the option is selected the backup is converted to a full read/write filegroup backup.
(Batch file-based policies) If you select for the , the backup is converted to a full read/write filegroup backup.
(Policies) If you select a filegroup for a differential backup, NetBackup does the following:
If the filegroup is the default database filegroup, NetBackup converts the backup to a full filegroup backup.
If the filegroup is a secondary filegroup and a backup of the primary filegroup does not exist, NetBackup converts the backup to a partial full database backup. This backup contains the selected filegroup and default filegroup.
If the filegroup is a secondary filegroup and a backup of the primary filegroup does exist, NetBackup converts the backup to a full filegroup backup of the selected filegroup.
For snapshot backup policies, you must create a schedule for NetBackup to successfully convert differential backups to full backups.
Note: NetBackup only converts a differential backup if a full backup was never performed on the database or filegroup. If a full backup does not exist in the NetBackup catalog but SQL Server detects an existing full LSN, NetBackup performs a differential backup and not a full. In this situation, you can restore the full backup with native tools and any differentials with the NetBackup web UI or NetBackup MS SQL Client. Or, if you expired the backup in NetBackup, you can import the full backups into the NetBackup catalog. Then you can restore both the full and the differential backups with the NetBackup web UI or the NetBackup MS SQL Client.