LTO drives are certainly capable of 64k blocksize, so the drive shouldn't be the issue. What SCSI controller are you using? I bet that is the problem and may need to be replaced if the registry change below doesn't help.
BE added some features to allow larger blocksizes for the newer larger drives and BE now only shows the largest blocksize supported in YOUR environment. In BE 10 I believe you could select 64k even if your environment didn't really support it. I suspect your SCSI card is limiting your system to 32k.
The parameter change to buffer size greater than 64 KB on Windows can only take effect if there is also a registry change to a parameter called ”MaximumSGList,” or Maximum scatter/gather List. This must be made for the HBA, which is connected to the tape drive. Use regedit from the run command line to start the registry editor.
Navigate the directory tree to
\\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\adpu160m\Parameters\Device\MaximumSGList
"adpu160m" is just an example of an Adaptec 29160 HBA registry entry. You will need to determine the proper driver name for the SCSI card used in YOUR system for the tape drive and replace it in that path.
The REG_DWORD MaximumSGList may not exist for a given HBA because the default is being used (I am guessing that for your card it defaults to 32k), so it may be necessary to create a NEW key from regedit.
The formula for calculating the value of MaximumSGList is as follows:
MaximumSGList = (Tape Blocksize (bytes)/4096) + 1
Or, set MaximumSGList to a value of ff (hex) if in doubt.
