We have a faulty Drive currently in NBU and I had it DOWNed. But recently when I removed the drives and re-added them there is a mismatch with Drive Name and Robot Drive Number. Like earlier Drive nae was like IBM.ULT3580.xxxx.002 and corresponding Robot Drive Number was Drive 4. Now after re-adding its appears as Drive 3 for IBM.ULT3580.xxxx.002.
So now to DOWN that drive I should consider Drive Name or Robot Drive Number?
Environment : NBU 7.7.x
Tape library : TL4000 (4 Drives)
If you have, in the library the drives physically in this order
IBM.ULT3580.xxxx.001 <<Robot drive postion 1
IBM.ULT3580.xxxx.002 << Robot drive position 2
IBM.ULT3580.xxxx.003 << Robot drive position 3
IBM.ULT3580.xxxx.004 << Robot drive position 4
Re-moving and readding in NBU may change the name, but should not change the drive position, as this is set by the library not NBU.
Run scan, on the robot control host and on the media server with the drives (if different) - the robot / changer part of scan will show the serial nubers of the drives in the position they are in in the robot. If you then run tpconfig -dl you can match each drive by it's serial number, and check it's drive position.
The only way I can think that the drive order changed, is if you added the drives manually and gave the wrong number, as opposed to just running the wizard and letting it sort itself out.