There are basically three methods of automatically cleaning robotic
tape drives:

1) Frequency.  Cleans the drives every N hours "whether they need it
   or not".  Requires cleaning tape to be available to NBU.  Not
   supported in SSO environments.

2) Hardware.  Put the tape into a special slot which only the robot
   can see.  Done when the drives reports a need for cleaning.

3) TapeAlert.  For hardware that supports it, the hardware can raise
   an alert which will be serviced by the software.  Provides the same
   on-demand cleaning as hardware based cleaning, but the tapes are
   managed by NBU (so you can have more than one, use more convenient
   reporting, etc).  YOU CAN NOT TURN THIS ON OR OFF, if it's
   supported, it's on (probably the cause of the original message).

Summary:  Frequency based is proactive, but may clean too often.
Demand based cleaning is reactive so it cleans less (possibly meaning
less wear on drive), but some people feel that it waits too long (once
the drive NEEDS cleaning...).  Personally, I'd chose TapeAlert over
hardware in most cases if I was using demand based cleaning.


Andrew Wilkin writes:
> Hi Tim,
> 
> I'm by no means an expert of this matter, I have asked questions of
> engineers and from what I've read/observed, this is how I understand the
> Hardware Cleaning takes place.
> 
> First off, you must have a cleaning cartridge in the Tape Library and it
> must "see it". I have a STY 9714 library, my cleaning tape MUST go into slot
> 00, this is a reserved slot. I also had an issue a few months ago were I
> couldn't use the front menu to exchange the cleaning tape, apparently this
> was fixed with a STY firmware upgrade as it started working after I had the
> engineer upgrade my libraries firmware.
> 
> Within Veritas turn-off it's capability for cleaning the drives. Veritas now
> won't monitor when the drives need cleaning. What you want to happen is for
> the library to "sense" when a drive requires cleaning and let the library to
> it rather than cleaning after X number of hours use.
> 
> The down side with the hardware cleaning is that you have to monitor when
> the cleaning tape has expired (after 20 uses). My library allows me to view
> how many times the cleaning tape has been used and also when the cleaning
> tape has expired it displays and asterisk (*) on the main menu of the
> library.
> 
> I'm running NUB of a HP platform, HP have a product called EMS which can be
> used to inform me when the Cleaning Tape has expired, at the moment I'm
> looking at this to build a script around it.
> 
> Hope this helps.
> 
> Regards 
> 
> Andrew Wilkin 
> Computer Systems Analyst 
> 
> Department of Information Technology & Management 
> Land & Property Information - New South Wales 
> 
> Panorama Ave 
> BATHURST, NSW, 2795, AUSTRALIA 
> 
> Ph: (02) 6332 8397 
> Fx: (02) 6332 8457 
> E-mail: Andrew.Wilkin AT ditm.nsw.gov DOT au 
> WEB: www.lpi.nsw.gov.au <http://www.lpi.nsw.gov.au>  
> 
> 
> 
> 
> 
> 
> 
> To:   veritas-bu AT mailman.eng.auburn DOT edu
> cc:    (bcc: Louis Francoeur/COMP/CA/PILS)
> 
> Subject:  RE: [Veritas-bu] Autocleaning of drive in STK L700
> 
> 
> 
> I have a question on a similar topic to the above.
> 
> I have a DLT7000 tape library. How does the (hardware) automatic tape
> cleaning work? I am currently using frequency cleaning at the moment but
> I have been told that you should not do this...
> 
> I have the cleaning tapes in the None group. Does the tape library ask
> netbackup for a cleaning tape and netbackup will process and clean the
> drive?
> 
> Cheers,
> 
> Tim.
> 
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-- 
Larry Kingery 
        For people who like peace and quiet: a phoneless cord.