I encounter the problem today when running backup job , it returns the error code 252 and 800. I check the drive is up in drive monitor and run the scan unix command to show the status is connectivity to NBU. I also run the inventory or robot arm to move the tape to the slot, it seems to be not hardware issue.
Can you please if anyone expert can assist me ?
Did you already use robstest command to verify if this is it a robot hardware problem? Take a look this TN, there are many steps to check whether or not this problem is on the side of the NBU..From what I saw in the screenshots that you sent, I dont think so it a NBU problem.
Over here you admitted that you have hardware errors - https://vox.veritas.com/t5/NetBackup/Tape-library-hardware-issue/m-p/831118
Please see all the questions that I have asked a month ago.
It is important that you determine where exactly the issue is -
the library? tape drives? connectivity?
Have you called your hardware vendor to have a look?
Have you checked OS and/or NBU logs?
In addition to the TN posted by @Thiago_Ribeiro, see this TN for robtest usage:
Robtest commands that can be used to test the SCSI functionality of a robot