Why would a tape drive fail shortly after being repaired?

It doesn’t happen very often, but sometimes shortly after we repair a tape drive for a customer, the tape drive gets read/write errors after putting it back into production.

Referring to one email we received from a customer:

However, the LTO5 that was manually cleaned has not changed behavior from before we sent it out.  It runs for 3-8 hours, then throws a generic “read/write error.”  It is unable to fill up a tape before failing.  I should point out that we also run the ITDT tool in house and have found it is a bit rudimentary for these types of drive issues.  (This drive had passed the ITDT before we sent it out). 

The possible reasons we provided to the customer:

  • Typically the problem lies with the customer using the same media that caused the problem in the first place.
Example of dirty interior of the top cover of a tape drive

With a debris laden tape drive, how could anyone not suspect that the media used in these tape drives? If the media also is contaminated, wouldn’t it re-contaminate the tape drive head once repaired? When you look at the debris, realize that there is a .02 micron spacing between the head surface and the actual data channel which houses the head. How can a 100 to 300 micron dust particle not affect the performance?  Just as a comparison, a particle of smoke is .08 microns visible dust is typically .3 microns.

  • The Worm Gear has become damaged.

This can happen either in shipping or by dropping the drive onto a hard surface.

We recommend using the DELL version of ITDT (ITDT-DCR).  The DELL version will run a POST B test which will test the ability of the elevator (Worm Gear) to move the head up/down.  Typically when writing more than a ¼ of a tape, the head will elevate up.  If the Elevator or Worm Gear is defective, the backup will fail at that point.

  • You are using the wrong type of media.

We strongly recommend only using the media recommended by the manufacturer.  HP tape drives: HP media, IBM tape drives: IBM media.  Fuji makes media for IBM and Dell so any of the 3 will work well.

We also found out that it is unwise to mix MP (Metal Particulate) and BF (Barium-Ferrite) media in LTO6 tape drives.  For example, in the IBM world and the LTO6 arena, only BF media is recommenced by IBM.  HP also made LTO6 media and it was MP not BF.  Mixing this media has caused us a lot of issues in our lab. No worries on the LTO7 media it is all BF media and all made by Fuji regardless of the exterior branding.  The LTO7 HP tape drives are IBM tape drives with HP exterior branding.

Summary:

As you can see, there are many factors as to why a tape drive sent into us, was repaired and tested but when you receive it back, it stops working shortly thereafter.

It is always best practice to use the media manufactured for the tape drive you are using. Also, do not put the tape that may have caused the issue in the first place, back into a repaired drive.

MidWest Technical

Categories

Subscribe!