NBU Duplication Multiplexing

Jim Turner — Tue, 03 Sep 2013 15:18:25 GMT

With Data Protector, an object copy allows you to multiplex numerous source streams down to a small number of target drives. For example, you could read from 30 VTL drives and multiplex those 30 streams down to 4 physical drives in an EML tape library.

It would appear looking at NBU 7.5 that multiplexing in this manner is not possible. If you only have 4 target physical drives, NBU only allows you to use 4 virtual drives in the VTL to read source images. If you have 30-40 source images to duplicate, this limitation creates an unnecessary performance bottleneck.

From NBU's duplication help:

Number of Read Drives - The number of drives to use for reading backup images. When you enter a number of read drives, the same number is entered into the Destination Write Drives field. You must have an equivalent number of read and write drives available.

Write Drives - The number of write drives. This value is the same as the number of read drives.

So is there no way at all to read 30 source images from a VTL with 30 drives and multiplex those down to only 4 target physical tape drives? The 1:1 read:write limitation badly constrains duplication performance.

topic NBU Duplication Multiplexing in Windows Server 2003

NBU Duplication Multiplexing