You can create up to four copies of the same backup image concurrently. Those copies are created concurrently by the Inline Tape Copy feature. If the images are created during a NetBackup policy job, all are considered original images. If the images are duplicated by using the NetBackup Administration Console Catalog node or during a Vault job, they are considered duplicate images.
You must configure NetBackup to allow a sufficient number of copies in the Maximum Backup Copies field for the NetBackup master server. (Configured in NetBackup Management > Host Properties > Master Server > server_name > Global NetBackup Attributes.) By default, the value is two.
All storage units must be connected to the same media server. Also, you must configure the storage unit to allow a sufficient number of concurrent jobs to support the concurrent copies (Maximum Concurrent Jobs or Maximum Concurrent Drives Used for Backup setting).
You can write images concurrently to the following storage units:
Network Data Management Protocol (NDMP) storage units only during Vault duplication and only one copy is allowed per duplication rule (NDMP is not supported during original backup). If the NDMP storage unit has more than one drive, the source and destination storage units can be the same.
Although specifying an NDMP storage unit restricts the number of copies to one, you can use multiple duplication rules to specify other storage units for images created by other media servers. For example, you can use one duplication rule to read an image from one media server and write a copy to an NDMP storage unit and use another duplication rule to read an image from a different media server and write copies to other storage units. (To specify multiple duplication rules in a Vault profile, select Advanced Configuration on the Profile dialog box Duplication tab.) Because of potential NDMP performance limitations, Symantec suggests that you duplicate between disk and tape drives that are directly attached to the same NDMP host.
If you create multiple original images concurrently during a NetBackup policy job, the backup time required may be longer than for one copy. Also, if you specify both Media Manager and disk storage units, the duration of disk write operations match that of slower removable media write operations.