Ok *SMers... see if this holds water. In order to calculate your tape
requirement. A given is that you do not add or delete a bunch of schedules
during the previous month:

1. q actl begindate=-30 search=ANR1214

     add up the daily archive and backup copy from primary to copypool storage
and divide by 30; now you have a per day
     average that is being backed up. Double the value because we have primary
and copy storage pools. Call this value
     "DailyAmt". For example the average copy from primary to copypool at my
location is 83gig... double this to 166gig to
     be the DailyAmt

2. select stgpool_name as stgpool, cast(mean(est_capacity_MB/1024) as
decimal(5,2)) as
gb_per_FULL_vol from volumes where status='FULL' group by stgpool_name

  add the average of each storage pool and divide by the number of storage
pools; this
  should give you an average capacity for a tape from all data types and using
compression.
  call this value "Cap"

3. DailyAmt / Cap = TAPES TSM WANTS PER DAY!

4. q actl begindate=-30 search=ANR1341

   This will give you the tapes that were deleted from your storagepools. Add
these lines
   up and divide by 30 days. This will give you the number of tapes reclaimed a
day.

This method will likely work better for a longer sampling period. When I did it,
I found that I am still about .5 tapes a day short of where I need to be.
Therefor, another 180 tapes can be bought or I can figure out how to reduce my
daily backup/archive by 1/2 the
amount of 1 tape or about 6 gigs per day... In fact, the former seems more
manageable than asking my boss for another $14K for tapes for the year
(again);-) Hope this info makes some sense... If there are holes in my logic,
let me know asap. Thanks -

George Lesho
Storage/System Admin
AFC Enterprises