Troubleshooting tape devices

SUMMARY

Tape problems can be caused by anything from bad connections, dirty tape heads, and worn out tapes, to SCSI bus problems. This article provides a description of many of the most common Tape device issues.

ISSUE

Tape problems can be caused by anything from bad connections, dirty tape heads, and worn out tapes, to SCSI bus problems. By far, the most difficult of these is SCSI bus problems. These do not occur often, but when they do, they pose a considerable effort to track down. Often support from the tape hardware vendor is needed to resolve SCSI level issues.  Unitrends uses a simple MTX SCSI command set and does not use drivers to interact with the tape device. 
 
If you are having tape system troubles, try the following:

  • Check the status of the tape unit itself
  • Verify the tape drive is idle and ready based on its LCD or other management interface.
  • Close all menus and UI windows, re-enter the browser, then stop tasker and restart it.
  • Test the tape. We have a command line tool to perform this action.This performs a variety of tests on the device, including writing tape labels, file set labels, and sample data-streams. From a command line, run “bpmenu –c”This performs a variety of tests on the device, including writing tape labels, file set labels, and sample data-streams. Select Task Manager > Misc > Tape Utilities > Tape Commands > TEST. If there is a configuration problem with the device it is usually detected in this phase.
 
Tape media errors occur
Tape devices can experience problems with writing.
If tape write errors occur in the logs, clean the tape device with a fresh cleaning tape. Keep in mind that cleaning tapes are designed to be used only a limited number of times and must be changed periodically, and should be used with a frequency indicated by your tape drive manufacturer (usually every 8 – 50 hours of use).
 
Additionally, for some of the 4mm and 8mm drives, the cleaning tape needs to be used two or three times in a row to fully clean the heads.
 
Try using a new tape to get better results. If a tape encounters a media error while writing data, the tape is marked full. Subsequent backups cannot be appended to this tape. Thus, if there is a single tape, all subsequent backup queued to this tape device fail until a new tape is inserted.

If the tapes are failing to load and you have stick-on labels on the tape try using tapes with preprinted labels instead.
 

Errors occur while writing a tape label
Most often, this occurs as a result of a timing issue in the tape drive’s firmware. The backup system performs a fast seek to the last dataset and determines that the tape has arrived before it actually has arrived. In order to fix this, open the Legacy UI, go to Settings > System Updates and Licensing > General Configuration (advanced).  Expand the “tape Commands” section.  Locate the “AdvancedTapePositioning” object and change the value from 1 to 0.   This will incur a penalty of taking longer to fastforward to an available space on tape when appending backups to a tape already prior used, but will solve some compatibility issues. 
 
 
The tape drive is not seen
Verify the following:
  • SCSI Termination is in place.
  • There are no adapters in the connection between the device and the backup system.
  • Shutdown both the backup system and the device. Power on the device and let it become idle/ready, then power up the backup system.
  • Make sure that the tape device is LVD/SD if SCSI
  • The backup system has a 68-pin high density connection for SCSI.
  • Run the following command to verify that the system sees the SCSI device.You should see 1 or more Sequential access devices (tape driver heads) and, if you have a jukebox, a changer:
cat /proc/scsi/scsi | egrep -B 2 "Sequential-Access|Medium Changer"
  • Run the following to additionally confirm our software recognizes your devicesThe output should list your changer as an “/sg*” device and the tapes as “/nst*” devices:
/usr/bp/bin/uarchive-scripts/tape.sh scan
  • A tape drive status may display, even if the drive is empty. For example based on the output of the above, run the following command with the sg* device indicated.The output should list the data transfer elements (drives) and all slots and their status. If you have a barcode reader additional information will be displayed about barcodes as well.
mt -f /dev/sg5 status
 
Tape drive is not available as a device to select
If you can configure your Tape Device and/or Jukebox in the legacy UI under Archive > Settings, but it does not display under Archive > media or as a device available when creating an archive schedule, this may be a licensing issue.  Though all modern appliances include support for Tape and NAS device archive (called Advanced Archive License), many appliances sold in 2010-2014 do not include that feature by default.   To confirm if your older device has this option, check Settings > System, Updates, and Licensing, License.  Review the feature string and ensure “ADX” is part of the string.  If not, contact your sales representative to purchase this option for your older unit. 
 
After replacing a tape device, jukebox is no longer functional or disappears from UI
This can occur because the jukebox was configured to be controlled by the older tape device. Contact Unitrends Support to have the old device information related to Parent Changer cleared from our database and you should then be able to properly configure the new device.   When possible, remove existing tape hardware configuration with the original device still online to avoid this issue. 
 
 
 
Tape restore fails with “File not found”
Tape restores as well as disk and NAS archive restores rely on a feature called ‘Quick Seek” to guess where data may be in a device.  On some tape systems, this can be inaccurate especially when tape hardware compression is enabled.  Edit the file /usr/bp/bpinit/master.ini.   locate the section [sctape] and the line QuickSeek.  Set the value to “No” and retry your restore.  
 

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