How to enable Disk Staging Storage Unit (DSSU) duplication to tape using multiple tape drives

When using NetBackup Disk Staging Storage Units (DSSU), duplication to the "final destination storage unit" is processed sequentially for each DSSU.

Assuming that the final storage unit is a media manager tape storage unit, this means that each DSSU will only use one tape drive - even if the DSSU contains 100 images that need to be duplicated and there are ten tape drives available.

The solution to enable efficient use of the tape drives is to create multiple DSSUs as outlined in the Related Article:

Disk Staging Design Considerations:

Each DSSU created can use a single tape drive to duplicate images (based on the disk staging schedule configured.)

However, one additional step needs to be taken. When DSSU duplication to the final storage unit takes place, the NetBackup media server that houses the DSSU becomes the "client" machine in the duplication process. In order for four DSSUs to write to four tape drives simultaneously, the "client" (in this case the DSSU media server) must allow at least four streams to be read at the same time.

This can be enabled for this one "client" machine by the following steps:

1. Open the NetBackup Administration Console
2. Expand Host Properties | Master Server. Open the properties of the NetBackup master server.
3. Select Client Attributes
4. Find the DSSU media server in the client list - if it is not present, add it
5. Highlight the name of the DSSU media server
6. On the right, select Maximum Data Streams and then enter the number of streams required (in this example, four)
7. Save and exit

The Global Attribute setting Maximum jobs per client also affects the number of streams allowed per client - but it affects ALL clients in the NetBackup environment.