=> On Tue, 11 Jun 2002 14:33:48 -0500, "Coats, Jack" <Jack.Coats AT 
BANKSTERLING DOT COM> said:


> Our current schedule is:
>   Weekdays 1300 till 2000 - update stgpool COPYPOOL rec=20
>   Weekdays 0900 till 1300 - update stgpool TAPEPOOL rec=10
>   Saturday 0800 till 2000 - update stgpool TAPEPOOL rec=10
>   Sunday 0800 till 2200 - update stgpool COPYPOOL rec=20

> Would it be a good idea to up the recovery percent?

I'd say, not just "yes", but "hell yes".

The lowest my reclaim percentage ever gets is about 50. Think about the
trade-offs:

If you reclaim percentage is 50, then your long-term average "wasted space" is
about 25%.  but this doesn't mean your costs have grown this much.

You've increased the total cost of your tape infrastructure by something like
5%.  Say you've got a 3494: you still only need one control unit (L frame),
one set of "smarts".  The rest is just extra storage slots.

What's worse: If you've got your reclaim percentages as low as 10%, you are
going to be moving a -lot- more data.  While you're saving money by reducing
your tape-slot count, you're also spending tape-hours.  Not just wear-and-tear
on the drives themselves (though that's possibly an issue) but actual
number-of-hours-in-a-day.  As soon as you're ready to buy your next tape
drive, think about the cost tradeoff, using more tapes to save drive time.


Allen S. Rout