User's Manual

hp StorageWorks File System Extender User Guide 199
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 a consolidated FSE implementation 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 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.