Tape library problems

Description

A tape library reports the same barcode in different locations.

Explanation

It could happen that the tape library reports the same medium barcode in a drive and in a slot

 

at the same time. In this case FSE writes an error message to the FSE error log file, and marks

 

both the medium and the drive as unusable. This happens when you manually move the

 

medium from the drive to the slot, and then start the library inventory rescan.

Workaround

To resolve this situation, perform either of the following steps:

 

• Manually move the medium back to the same drive and clear the slot.

 

• Clear the drive and trigger inventory for the slot to which the cartridge was moved.

 

Note that the full inventory rescan is not recommended, because it can be very time-consuming.

Description

On the consolidated FSE system or FSE server with an HP StorageWorks MSL library connected,

 

after you query for detected SCSI devices, only the medium changer of the library appears in

 

the list.

 

(Red Hat Enterprise Linux system specific)

Explanation

The Red Hat Enterprise Linux kernel only detects devices with a LUN of zero. HP StorageWorks

 

MSL libraries use different LUNs for each library unit (medium changer, tape drive, and

 

embedded router). As a result, only the medium changer is detected and the library cannot be

 

used.

Workaround

Proceed as follows:

 

1.

Add the following line into the file /etc/modules.conf:

 

 

options scsi_mod max_scsi_luns=255

 

2.

Using the mkinitrd command, rebuild the initial RAM disk.

 

3.

Restart the system.

 

4.

Invoke the following command:

 

 

# echo "scsi scan-new-devices" > /proc/scsi/scsi

 

5.

Inspect the output of the following command to determine if all missing devices have been

 

 

detected:

 

 

# cat /proc/scsi/scsi

 

 

If the missing devices are listed, add the command you ran in step 4 to your Linux system

 

 

startup script, in order to ensure that all devices are accessible after the Linux system is

 

 

started. You can now start using the FSE implementation.

 

 

If the missing devices are not listed, proceed with the next steps.

 

6.

For each missing device, invoke the following command. In place of parameters H, B, T,

 

 

and L, specify the HBA number, SCSI bus number, target SCSI ID, and LUN of the device,

 

 

respectively:

 

 

# echo "scsi add-single-device H B T L" > /proc/scsi/scsi

 

7.

Run the command from step 5 to verify that the missing devices have been detected.

 

8.

Add each command that you ran in step 6 to your Linux system startup script.

250 Troubleshooting