On Mon, Oct 13, 2008 at 04:54:22PM -0400, Justin Piszcz wrote:
> Also I've read / heard its best to let LTO-3 LTO-4 drives set the tape  
> alert flag when they need cleaning vs. cleaning drives at intervals 
> (which is recommended for sure with LTO-2) -- what have you observed?

I'm not sure which you're saying is recommended for LTO-2.  As far as
I'm aware, periodic cleaning is not recommended for any model of LTO
drive.  This is documented for HP and IBM drives:

HP
    Should I do regular cleaning like DDS?

    The HP Ultrium drive is designed to require very minimal
    cleaning. The internal head cleaner provides an effective
    preventative cleaning against head contamination. Regular cleaning
    using cleaning cartridge is not necessary. Do not use a cleaning
    cartridge unless the drive requests it and the Use Cleaning
    Cartridge

IBM
    The IBM Ultrium LTO Tape Drive was intentionally designed to be
    self-monitoring and self-cleaning. Therefore, the IBM recommendation
    is not to manually clean the tape drive, but rather to use the
    automatic cleaning function provided with the library or by your
    application.

    Each drive determines when it needs to be cleaned and alerts the
    library or your application.

    In order to prevent recontamination of drive surfaces, you are
    limited to using a specific cleaner cartridge a maximum of 50 times.

    Note: Do not manually initiate drive cleaning unless requested by
    support engineers. LTO drives are self-cleaning and will require
    infrequent cleaning using cleaning cartridges.

I found the document I was thinking of.  HP LTO-1 uses 18.5 meters of
cleaning tape, other models use 5.5 meters.  So you get 15 on an LTO1
and 50+ on LTO-2 and LTO-3 (and I assume on LTO-4 as well).

I love whoever proofread this sentence.  (...up to at least..)

   IMPORTANT: A cleaning cartridge can be used up to at least 50 times
   (LTO2 and LTO3) or 15 times (LTO1). The cleaning cartridge is ejected
   immediately if it has expired or if it is not an approved Ultrium
   cleaning cartridge. Discard it and use a new one.

Technically, because the cleaning usage algorithm isn't mandated,
there's no way for a universal cleaning *tape* manufacturer to know what
the usage will be beforehand.  A manufacturer could use more or less.
However, it appears that both IBM and HP use 50 on recent drives. 

-- 
Darren
_______________________________________________
Veritas-bu maillist  -  Veritas-bu AT mailman.eng.auburn DOT edu
http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu