HP BB118BV - StorageWorks Data Protector Express Package User's Manual & Technical Reference page 218

D: drive that are both on the same physical disk, a single stream may be more appropriate to prevent
disk thrashing. If the volumes are on separate disks, two streams can be used.
There is no load balancing logic in place to intelligently assign streams based on their data size, but any
zero-byte streams will be grouped with other streams to avoid using media unnecessarily.
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Working With Devices