I posted this stuff a while back... might be useful:

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
AFC Enterprises








Kurt Beyers <kurt.beyers AT PANDORA DOT BE>@VM.MARIST.EDU> on 01/24/2002 
02:24:10
PM

Please respond to "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>

Sent by:  "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>


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Subject:  size of library


Hello everybody,

TSM does a pretty good job on the tape management by space reclamation and
copying the primary pools to copy pools.

But I'm wondering how I can estimate the size of the library (number of
slots, type of drive) to reach this steady state of tape usage. Of course
I've got the following information:

total amount of data to be backupped (GB)
the number of versions I keep of the files
space reclamation of tape occurs when there is 55% free space on the tape

How can I estimate the number of tapes I'll be needing based on this info?
Are there any rules of thumb to size the library? Do I still need
additional info to calculate the library size?

Any suggestions /hints are more than welcome.

Thanks in advance,
Kurt