Here's what Quantum recommends:

"Q: Is head cleaning required for a DLT drive? 
A: No periodic head cleaning is required. The Use Cleaning Tape indicator on
the front panel of the drive will light when the drive needs cleaning. A
cleaning is completed simply by loading a special cleaning cartridge into
the drive. The tape path and head is cleaned as the media on cleaning tape
is taken into the drive. The cleaning process takes a little more than a
minute, and when complete will both turn off the Use Cleaning Tape indicator
and light the Operate Handle indicator. Then the cartridge can be removed.
No other cleaning methods should be used with the DLT drive mechanism. Since
the head and tape media have been carefully designed to be "self-cleaning",
it is possible that the Use Cleaning Tape indicator will never light and a
cleaning cartridge will not be needed.
If dust, heavy usage, or contaminants create the need for a cleaning, the
Use Cleaning Tape indicator will light. If the use of a particular data
cartridge repeatedly lights the Use Cleaning Tape indicator, the cartridge
may be damaged and need to be replaced. "
        (http://www.quantum.com/support/csr/faq/csr_faq_dlt.htm
<http://www.quantum.com/support/csr/faq/csr_faq_dlt.htm> )

        -----Original Message-----
        From:   Michael Traves 
        Sent:   Saturday, April 08, 2000 4:55 PM
        To:     Veritas-bu AT mailman.eng.auburn DOT edu
        Subject:        Re: [Veritas-bu] Re: DLT Cleaning


         > I'd just like to finally get to the bottom of this kind of
statement. I
        > believe it to be
        > popular myth!  I too also believed that excessive cleaning of DLT
drives
        > would
        > increase headwear however I've recently been told categorically by
an STK
        > trainer
        > that a DLT cleaning tape is simply a standard tape that has not
gone
        > through the
        > burnishing process. As such it's a standard tape (same thickness,
same
        > material) > as a data tape only not polished. Since it's movement
over the
        > heads is identical

        A DLT tape drive is typically described as "self-cleaning", and as
such
        should only be cleaned when it actually requests it.  Excessive
cleaning
        beyond this does increase head-wear -- just ask your STK CSE.  They
won't
        enjoy flipping drives due to head wear because you're cleaning the
drives
        too much.

        Prior to NBU 3.2 (and with other backup products), the normal
recommendation
        was to ensure that the robot did the drive cleaning when the tape
drives
        asked for it, and not to schedule it through the software (which
only
        understood the N hours of usage rule).  This had the drawback that
the robot
        might be sitting there with a used DLT cleaning tape waiting for a
        replacement to be loaded, with no operator notification.  If mount
timeout's
        were too short, a drive could also inadvertently get marked down by
the
        software, due to the robot's issuing a drive cleaning.  As well,
only some
        vendors robots supported self cleaning options.

        I haven't played with the NBU 3.2 feature for properly detecting
drive
        cleaning and managing it itself -- if it works well, it means that
you can
        now at least monitor cleaning tape usage and trigger an
appropriately timed
        action.

        And as a final point, cleaning a drive every "N hours" when it
doesn't
        really need it also costs you extra $$.

        Cheers,

        Mike


        Michael Traves              mtraves AT esitechnologies DOT com
        Senior Architect
        ESI Technologies           www.esitechnologies.com

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