Reinhard said..
> I am thinking on increasing the number of backup versions in our
> default management class, and would like to know how this affects
> the database space needed. There are estimates on the number of bytes
> needed for a file (ca. 600), but do estimates on the costs of additional
> backup versions exist?

I use an estimate of 20% of all files on a desktop machine change
over time, but any estimate in this area is risky.  Some servers
hardly change files at all; some change almost everything daily.

Your activities and those of your clients also affect this.  For
example, a selective backup will make another copy (of everything).
Relabeling a drive/filespace will make another copy of everything.

So, it depends.  If 20% of files are changed and your policy
maintains one inactive file, then you have 120% of drive/filespace
size required. If you keep a second inactive copy, then you might
estimate an upper bound of 140% of drive/filespace size.  If complete
copies are made, then the requirements may become 200% and 300%.

Unfortunately, neither the client nor server appears to help in
determining active vs inactive files.  At least the server should,
for central management, and the client should, if the client pays
for data stored on the ADSM server!

cheers,

Wayne T. Smith
Systems Group -- CAPS        internet: wts AT maine.maine DOT edu
University of Maine System   BITNET/CREN: WTS@MAINE