Assuming you are using IBM tape drives, see the "IBM Tape Device Drivers 
Installation and Users Guide".  
The cut/past below is from the section on Dynamic Load Balancing.  This works 
differently than disk multi-pathing.


=================================================

The dynamic load balancing support optimizes resources for tape devices that 
have
physical connections to multiple Host Bus Adapters (HBA) in the same machine.
When an application opens a device that has multiple HBA paths configured, the
device driver determines which path has the HBA with the lowest usage, and
assigns that path to the application. When another application opens a different
device with multiple HBA paths, the device driver again determines the path with
the lowest HBA usage and assigns that path to the second application. The device
driver updates the usage on the HBA assigned to the application when the device
is closed. Dynamic load balancing uses all Host Bus Adapters whenever possible
and balance the load between them to optimize the resources in the machine.

For example, consider a machine with two Host Bus Adapters, HBA1 and HBA2,
with multiple tape drives attached. Each tape drive is connected to both HBA1 
and
HBA2. Initially, there are no tape drives currently in use. When the first 
application
opens a tape drive for use, the device driver assigns the application to use 
HBA1.
When a second application opens a tape drive for use, the device driver assigns
the second application to use HBA2. A third application would be assigned to
HBA1 and a fourth application would be assigned to HBA2. There would be two
applications using HBA1 and two applications using HBA2.

If the first application finishes and closes the device, there would now be one
application using HBA1 and two applications using HBA2. When the next
application opens a tape drive, it would be assigned to HBA1, so again there
would be two applications using HBA1 and two applications using HBA2.
Likewise, if the second application finishes and closes the device, HBA2 would
have one application using it and the next application that opens a tape drive
would be assigned to HBA2.

The dynamic load balancing support is independent from the automatic failover
support. Regardless of the path assigned initially for load balancing, if that 
path
fails, the automatic failover support attempts recovery on the next available 
path.


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