SCSI Port 0 Shows down Intermittently on NSR e1200-160

[Sivaramakrishna_1]

Hi,

MSL 6030 having 2 drivers with E1200-160 router. Approximately around 4-5 days servers loose the connectivity to Medium Changer and One Tape Drive. One Tape which is connected to scsi port 1 of NSR is getting detected. On NSR the status of SCSI port 0 Shows as down. If we perform discovery again it's showing as UP, but again issue repeates frequently. I am attaching NSR report. Pls help on this.

[Marino Meloni_1]

looks like you have a connectivity problem on the scsi bus O, where you have the drive and the controller daisy chained, suspected problem may come from cables, terminator, drive controller or the scsi port of the NSR.

you are also facing FC problem with elatic errors on the connection with the Switch, check the cable or try to clean the head of the cable itself.

[Curtis Ballard]

The recommended SCSI cabling for the drive and library controller has changed since the manuals were printed and you should cable from the NSR to the library controller, from the library controller to the drive, then terminate at the drive. Be sure to check all connectors for damaged pins any time you have them off.

[Sivaramakrishna_1]

Hi Meloni/Ballard,

Thanks for your reply, We have already replaced cables of SCSI port 0. I checked the cabling diagram from HP Site, it is shown as
NSR SCSI 0- Drive0 - Controller -
Terminator.

NSR SCSI 1 - Drive1 - Terminator.

Is there any document for new cabling.

Pls suggest

Regards,
Siva

[Curtis Ballard]

Unfortunately the documentation has not been updated so I can't point you to a new published document for the changed SCSI cabling.

If you want to review the T10 standards documents at T10.org you will see that both the originally recommended cabling and the modified cabling I've recommended are both approved by the standards.

The terminator pulls the signal lines to the off state and the closer you are to the terminator the sharper the transition will be so having the drive at the terminator is the best location for the drive since it has the highest data rates. The signals are cleanest at the terminator and at the HBA and are more rounded in the middle of the bus.