Ok, I think I might have discovered something key to my poor performance..

I'm watching the duplication job that the vault spawns to copy the backup from 
VTL to LTO3.  For the bptm process that is doing the read from VTL:

<2> io_init: buffer size for read is 64512

Obviously, I want to use a high buffer size for reads, but I already have 
SIZE_DATA_BUFFERS and SIZE_DATA_BUFFERS_RESTORE set to 262144 so I'm not sure 
how to modify that particular buffer setting.

To somebody else who asked, the connectivity between devices is a Qlogic 9000 
series switch and a pair of QLE2462s in the T2000.  4Gb all the way through 
from host to switch and switch to the VTL front-end port.  I think the LTO3 
drives are only 2Gb but that should be plenty.  Using seperate HBA ports for 
the VTL luns and LTO3 drive.

/etc/system is at default.. no tuning done there since this is a Solaris 10 
system with 8GB of memory (so 2GB for shared memory).

Using 128 buffers, 262144 size.  Goign to increase the # since the system has 
plenty of memory.

Also, in dd tests, I'm able to achieve line speeds on the HBA writing to the 
VTL so I know its up for the task.  I gotta think that the 64k buffer used for 
reading though is killing the performance.

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