Does  any one out there have a formula they use to calculate the number of
tapes they will use for an instance of TSM
I've tried to start with
          1) size of file systems to backup x 1 because you have at least 1
backup version of every file on the systems you'll back up(roughly)
          2) estimate the percentage of data that changes in you
environment daily, multiply that by the number of versions you'll keep
          add numbers 1 and two together to get a number that equals the
amount of data you'll have in your backup system onsite.
     here's where it gets fuzzy. Somehow you have to calculate the amount
of data you'll have co-located and non colocated. Find an average of the
capacity  your getting on your tapes. Then you'll have a number of what
your on-site capacity should be. Now you can double that if you're using
DRM and then somehow calculate in the factor of the re-use delay parameter
for the storage pools?????????????????