One thing to keep in mind is that FibreChannel is not involved at the initiation of tape mounts for a 3494 tape library, as that operation involves communication with the 3494 library manager over networking. Tape loading is then a mechanical operation, supervised by the drive firmware. Unload would be initiated through host-drive communication, which would be over FC, the mechanics again supervised by drive firmware. Having current drive firmware can improve general performance.
In your migration to a new computer platform you ostensibly now have new HBAs in place to interact with the tape drives. It is very important to have current HBA firmware in place, for proper communication and conveyance of orders. Note also that host application changes can require appropriate HBA firmware levels, and that such changes can affect interactions at mount time. (For example, at the TSM 5.3.3.0 level, new functionality was added to detect medium type via a passthrough SCSI call at mount time.) Also, I hope you aren't mixing tape and disk on an HBA, which IBM recommends against. (Disk has priority over tape in HBA operations.) Richard Sims
