Dell PowerVault DR4100 - Manual (Page 19)

19 Setting Up the Dell™ DR Series System on Symantec NetBackup to Use Virtual Synthetic Backup | February 2014
In New Storage Unit, enter a Storage unit name, Storage unit type as Disk, Disk type as 16.
OpenStorage (DELL), Storage unit configured for as Backup. Select the disk pool that was created
in steps 7- 13, and select the media server that will be used for backup.
17. Make sure that the Storage Unit is listed after creation.