DLT Cleaning tape.

[MARREEL Chris_1]

Hello,

I understand that a DLT cleaning tape can only be used 20 times (and not once more than that).

How can a cleaning tape know how many times it has been used?
How can we (system admin) know how many times the cleaning tape has been used if it is inside a tape-library and the omniback-software will clean automaticaly ?

Share your knowledge, so we all become smarter...

Greetings,
Chris MARREEL

[Eugeny Brychkov]

Chris,
within library, please check if you applied correct cleaning tape barcode label (beginning from "CL"). Check if your backup application can count cleaning tape usage (by its barcode or sense status returned by drive).
Check that your library has latest autochanger and drive firmware.
You should check backup utility manual. Maybe you need to turn library autoclean option off as it may cause backup to fail and backup utility confusion
Eugeny

[JohnWRuffo]

Most DLT Cleaning Tapes have a generic paper label in the case that allows you to "mark" each time you use it. Once you have filled in all the squares, dispose of it properly...
-John

[Angus Crome]

For omniback, you can use the /var/opt/omni/logs/cleaning.log file. Everytime you change the cleaning tape, clear the file. You can then write a script (and possibly incorporate it into the mount script) to mail/page/etc when it has been used 20 times.

I believe there is a generic report under the reporting tools, to do this as well.

[MARREEL Chris_1]

thanks, for sharing your knowledge.

I will indeed look at the cleaning.log file to see when Omniback has used the cleaning-tape, and each time I need to replace the tape I will add one line to the cleaning.log with a date-entry so I know when the last time the cleaning cartridge has been replaced.

There is still one question 'unanswered':
Does anybody know HOW the tape-drive tell how many times a cleaning tape has been used ? What mechanisme is used ? Is there something written to the (beginning) of the tape? I have opened an expired cleaningtape and there is NO electronic inside the cleaning-cartridge.

Greetings,
Chris MARREEL

[Ted Ellis_2]

Chris.. there is no mechanical/physical limitation to using a cleaning tape more than 20 times. If you have a standalone DLT drive... you can take a fresh cleaning tape and run it through the tape drive 100 times and it will not complain. 20 times is the standard limit for how many times it should be used before replacing... the counter for use is maintained on either the hardware (the tape library robotics) or the software (Omniback). We have cleaning tapes in out tape library with the "CL" prefixed labels and the library reads that and keeps trazck of the number of times it is used.....

Ted

[MARREEL Chris_1]

Ted, thanks for your answer, but I don't fully agree with it.

I used the user-interface of the tape-library (surestore 2/20) to load the cleaning-tape in the drive, so omniback at that point wasn't aware a cleaning was in progress and the tape-library complained that the cleaning-tape was 'expired'.

I have then replaced the cleaning-cartridge with a new one, BUT re-used the SAME bar-code-label (beginning with CLN...), and then the cleaning-tape was accepted and the tape was successfully cleaned.

I don't have any experience with stand-alone DLT's, but I think the tape-library is controlling it, but not via the bar-code-label.
Question is HOW....

Greetings,
Chris MARREEL

[Vincent Farrugia]

Hello,

Basically, the cleaning tape cartridge expires FOR REAL. When it cleans a drive, it does NOT run through the whole tape. It runs to 1/20th of the tape. The cleaning tape is special; it has a certain abrasivity to it so that the heads of the tape drive becomes clean again. Too much cleaning actually is detrimental to the head for this reason.

When the next cleaning is required, it goes to the next 1/20th slot and uses that part, and so on, until the 20th part is used. When this is used, the cleaning cartridge is rejected, no matter what bar codes you use.

So if a cleaning cartridge says it is expired, beleive him :-) Even if you manage to force it to clean again from the beginning, it is of no use, since the abrasivity of the tape will be gone from prior usage, and no cleaning will be performed.

HTH,
Vince

[MARREEL Chris_1]

Vince,
This seams acceptable to me. This means this 'abrasive' thing on the tape is disapeared after the head has once passed this part of the tape.

I know a DLT and an ULTRIUM should only be cleaned if the tape-drive asks for it.

Thanks,
Chris MARREEL

[David Ruska · Accepted solution]

Vincent's description is accurate:

> When it cleans a drive, it does NOT run through the
> whole tape. It runs to 1/20th of the tape.
> The cleaning tape is special; ...

If anyone cares, I'll give some more detail.

A DLT cleaning tape is unburnished DLT III media (1200 feet long). Unburnished media means it has not been polished in the production process to remove roughness.

The drive recognizes a cleaning tape by the presence of double BOT holes near the splice on the tape. When it identifies a cleaning tape, it searches down the tape for an unused section. During cleaning, the drive writes data on the tape to indicate a section that has been used.

The cleaning tape is divided into 20 sections of 60 feet each. When the drive finds an unused section, it makes ten passes over that section, stepping the head up and down in the process (without any head tilting on DLT7000 and 8000s).

The reason the drive uses a new section of tape each time is: 1) Some of the abrasiveness gets lost. 2) The previous cleanings may have picked up some debris from the head, and you don't want to transfer it back.

A cleaning tape is at least 10X the abrasiveness of a regular (burnished) tape, and therefore you don't want to overuse it. As mentioned, ONLY clean DLT and LTO drives when they request it.

There are two ways to track cleaning tape usage:

1) manually - fill in one square on the provided bar-code label.

2) via software - use a special bar code which the backup software can recognize and track. Many applications allow you to configure tape libraries for 'clean on request', which manages cleaning automatically. Do not use 'periodic' cleaning.

You can tell an expired cleaning tape, because the drive will not clear the cleaning light when the cleaning tape is unloaded. Some tape libraries (e.g. SureStore 20/40/60 slot) will tell you the cleaning tape is expired via the front panel.

Finally, cleaning tapes are most effective at removing chemical staining (from components in the tape binder) from the head. They are less effective at removing contamination, as the cleaning tape may just spread it around. In cases where contamination is suspected (e.g. paper fiber, carpet fiber, smoke, ash, dust), using a new cleaning tape 3 times in a row may help to clear it up (then clean up the environment!).

[Vincent Farrugia]

Hello,

Thanks David for your very accurate information (as always). Took note of that :-)

Regards,
Vince

[MARREEL Chris_1]

David,

Thanks for you in-depth answer, it was this background-information I was looking for.

Thanks and greetings,
Chris MARREEL

[David Ruska]

Chris,

> Thanks for you in-depth answer...

You welcome. Thanks for the points :-)

Just one more bit of trivia:

The cleaning process writes on the tapes, but it doesn't seem to matter what the setting of the "write protect" switch is. Even protected, the drive will turn off the write protect light when it determinies that it's a cleaning tape, and properly write each segment as used.