Do you actually have that many tape drives in your environment?
NBU automatically assigns Index numbers in the order that tape drives are added.
First drive - Index 0
2nd drive - Index 1, etc.
If you look at tpconfig Command reference, you will see that the index # is the 'key field' or main identifyer for the tape drive.
'tpconfig -update -drive drvindex ' is used to change attributes for the drive.
IMHO, the only way to create a new index, is to delete and re-add the drive.
Looking at 'tpconfig -add' command usage, it looks like it may be possible to specify the index number. So, manual process by the looks of it.
I disagree. I have a data domain 9800, with over 300 drives defined. My highest robot drive index is 304.
Is it possible that this 255 limit is per media server? Because the most drives I have per media server is about 30.
Before this I had three data domains EACH with over 300 drives, I had over 1000 drives defined, and NetBackup drove them like a champ.
The only issues I ever had was SHARED drives, there is definitely an issue with too many shared drives.
My understanding is netbackup uses the drives alphabetically by the drive names, so you can modify the names so it rotates through the HBA.
The drive index is the drive number on your data domain, review to see if you have holes in your configuration.