Apologies for all of us missing your post.
There is no good reason for NBU to be faster to VTL but slower to physical tape as a result of the upgrade.
NBU has no direct access to devices - it uses the OS device paths and drivers to pass data to drives.
You need to take NBU out of the picture - use robtest to manually load scratch/test tapes into virtual and physical drives. Use something like 'tar' to backup same data locally on the media server.
SIZE and NUMBER_DATA_BUFFER files must be in /usr/openv/netbackup/db/config folder on the media server.
Use bptm log on media server to verify buffer sizes and trace throughput.
