connect/disconnect FC device to/from running system

[Frantisek Repkovsky]

Hello,
We have HP Ultrium tape library connected by opt. cable to fibre channel adapter on HPUX 11i (rp7400) system. I'd like to ask you if I can connect/disconnect tape library to/from running system without risk of any system problems.

Thanx

[Michael Tully]

There is always an element of risk when disconnecting cables from a system, even FC cables. Although I cannot say 100% for sure that your system will not crash, your best bet is to make sure that the end you have disconnected has been plugged. If you take out the cables from your server, then plug the cards. I've never seen a system crash where a tape library was involved, but I have when it has to do with disks with FC.
Good luck with whatever your decide.

[Zeev Schultz]

Depends on the type of FC/SAN - loop,fabric or
point-to-point.In your case I assume it's either loop or point-to-point.You can see for sure with fcmsutil /dev/tdX (1,2.. for X) for
TOPOLOGY=.Basically FC adapters are auto sensing,much like lan cards.So when you disconnect the cable it'll go to sort of DEAD state without impact on running OS.However!If you have your server connected to a FC-to-SCSI bridge (2 or 4 scsi ports to 1 FC) and set (in bridge) soft setting
for AL_PA (loop addresses for ultrium drives) so next time you connect library back the device files could be different!That impacts some of backup software products like OmniBack.

Regards,

Zeev