I'm going to use a block-level backup solution to backup a Hyper-V server running SBS 2008 plus two additional instances of Windows 2008. It's fairly lightweight in terms of relative use. Total file sharing size is only around 100GB. Size of Exchange is 50GB. I'm thinking that the total size of all backed up volumes will be in the neighborhood of 300GB.
I'm not sure how I would collect data on the existing system to estimate this. Storage growth is fairly low; less than 20GB over the past year which includes file storage and Exchange.
What I'm trying to do is estimate how much backup history I can get on 1TB media, backing up in full once every 24 hours, 7 days a week. Again, this is block level backup, not file level. Thus I'm trying to figure out how many blocks might change per day.
While I know there is no clear-cut answer to this, would 1% be too low? Would 10% be too high? Which continent is my ballpark on? Thanks.