When the backup policy is configured to perform a differential incremental backup, only the files that changed since the last successful backup are backed up.
On Microsoft Windows systems, you can configure differential-incremental backups to use either the datetime stamp or the archive bit.
For datetime stamp use, differential-incremental backups include all files with a datetime stamp that is more recent than the last full or incremental backup.
For archive bit use, differential-incremental backups include all files that have their archive bit set. Archive bits are cleared on differential-incremental backups if all files are backed up successfully.
See General tab.
Only the NetBackup master server can perform incremental backups.