From:   Stanley, Jon [mailto:Jon.Stanley AT SAVVIS DOT NET]
>Is there any way to quantify the amount of space that will be reclaimed
via changing a retention policy and letting expiration run until it's
done? For example, the current policy is 180 day/8 versions.  If I
change that to 30 days/3 versions, how much space would I gain?  I'm
sure it's quite substantial, but I need to be able to quantify it.<


You're asking an open-ended question. The answer is entirely dependent upon 
information you didn't supply. How much data are you backing up? How old are 
the files? How many copy pools are you using? And even with this information, 
it's impossible to tell, because we don't know how old each file backup is.

--
Mark Stapleton (stapleton AT berbee DOT com)