Take a look at the redbook Getting Started with Tivoli Storage Manager:
Implementation Guide. It tells you how to calculate the number of tapes.
" " wrote:
> 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?????????????????
