I have stopped all the currently running and future backups, so that no backups would be fired in between. I have stopped 'networker' service, rebooted the tape library and restarted the 'networker' service again. The status of the drives went blank, but when I tested for a backup, the tape got mounted on the drive and the drive went in service mode again.

You might have stopped all backup operations but incase there is a pending mount, then the backup server will tr to mount a tape in the drive. Go ahead and kill the server - nsrlcpd. Then wait for the library to come to a ready state again, change the drive state to enabled. Once done and you are sure that it is in an enabled state try a mount on this drive.

I would also suggest you to do a tail -f on the daemon.raw and monitor what is logged in the daemon.raw.

As crazyrow mentioned, you should have a look at the daemon.raw file which will obviously tell you more.

If you do not understand the messages, i would first

  - load but not mount the media

  - try to mount it next (this will verify the label so it will read)

  - try to run a backup (which needs the tape to be not write protected)

Each time, carefully verify the drive status.

BTW - if you just labeled new (virgin tapes) - NW will still disable/put in service mode the device after 20 attemps/tapes.

Veeeeeery old NW behavior.

So the best practice is not to label more than 20 fresh tapes in a device within one job.

I think, results would be the same as the output of series of commands I executed (mentioned in the Note section of my question).

Would that work, according to you?

it can be a possibility that there are errors on the drive that are continuous and is causing the drive to go back to service mode as soon as you enable it. Check the status of the drive on the library panel and also on the OS.

No backup is running. I have already stopped all the backups from the NMC.

Could you please elaborate on the procedure which should be followed from the Admin GUI, so that I can take those tape drives out of Service mode?

It might be possible that you cannot change the mode if there is a pending/inactive backup process.

In such case you have to stop it first.

Additionally, i encourage you to use the Admin GUI as it will display a clear reason.

In the NW Admin GUI, go to 'Devices' and browse through your library and the device(s) inside.

select the jukebox or the tape drive,

  open its Properties

    go to the General tab

      change the Status

Things look fine on the library console. On OS side, nsrjb shows the status as 'service mode'.

Yes, they are enabled.

I also tried disabling and re-enabling them. But it did not help.

Aha - these are jukebox drives.

What about setting the jukebox to 'enabled' as well ...