> I attended a presentation from
> Curtis Preston that said high 90% is an excellent utilization rate,
> with some real-world hovering around 40-60% (I think) so I doubt all
> of our volumes are being utilized 100%.

First, let me clarify what I say in the backup schools, as this doesn't
quite match what I'm saying, but it's close.  (BTW, 15 more free
seminars to go! For schedules, check out
http://www.backupcentral.com/content/view/157/47/ ).

I say that many people don't look at the percentage of their tapes they
are utilizing, and they don't think about what this does to their
overall cost.  I gave an example of a specific (anonymized) customer who
had a 40% tape utilization, and said that for every percentage point we
could increase their utilization, we could save that customer $150K -
$450K, depending on which tape type we were talking about. (They use
several types.)

The thread seems to be leaning to me suggesting that I was talking about
drives that skip tape, which some believe don't exist.  That's not what
I'm talking about.  What I'm talking about are behaviors/configurations
that cause you to not send enough data to a tape.  An extreme case would
be if you require every client to have their own pool.  That would
obviously significantly increase the number of tapes you would need and
would create a lot of empty tape out there.  Less extreme, but totally
normal things that decrease tape utilization are listed below:

1. Turning on "allow multiple retentions per media" (the funny thing is
   that people who turn it on think the opposite)
2. Excessive pool count
3. Excessively higher number of unique mpx settings
4. Excessive number of media servers or SAN media servers (prior to
6.5.1)
5. Excessively small tape library, as it causes you to ejecting original
backups out of the library as soon as they're made and before they're
full

I did not say that you should be able to achieve 90% of your tape
capacity.  You may be confusing media utilization with what I said about
tape DRIVE utilization.  I do believe you should be shooting for 90% of
your THROUGHPUT capacity, which is your native throughput rate times the
average compression ratio you're getting on your data.  Failure to do so
causes more than cost issues.  It will cause your drives to fail more
often as they will be shoeshining.

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