I had one drive defect and one ok. NetBackup not even try to load tapes, no status 800 only : no drives are available.
When I tried to read the content of a tape, NetBackup mounted the tape but never begin to read it.
Erasing and cleaning a tape seem to be the only things to work.
After reading on the case of no drives are available, I note the status 800, but it was not the case here. I decide to rollback from NB 6.5.3.1 to NB 6.5.3. Same thing,no drives are available even if one drive is up and running and the other was delete from NetBackup.
I rollback from NB 6.5.3 to NB 6.5 and suprise, it worked. I made some tests and NetBackup recognise that at least one tape drive was running. I re-install NB 6.5.3 and the problem came back. It seems that some verification about the physical ressources such as tape drive prevent backup to be take if one drive is bad. The problem appeared with NB 6.5.3 and is still there with NB 6.5.3.1.
Actually, I'm running NetBackup with one tape drive at the version NB 6.5. As soon as the second tape drive will be replace, I'll re-upgrade at NB 6.5.3.1