Barry Callahan wrote:
> 
> Last week, I stumbled across a webpage that had a discussion on how big
> to make your holding area, and I can't seem to find it anymore.  I don't
> remember where I saw it.
> 

The holding area should be at least as big as to  be able to accomodate
the largest amount of backup data that would fit on a real tape (not on
estimated tape length). Taking the limit, a minimum holding disk area
should have the capacity of exactly one tape (assuming runtapes to be 1,
otherwise multiply by runtapes). Since you might have a tape library and
the backups might fail on many consecutive runs, and/or you might be
arbitrarily slow in flushing the contents of the holding disk to tape
while failing images may keep coming into the holding area at the steady
pace set by  runspercycle, I postulate there is no upper limit to the
capacity of the holding disk. A truly mathematical proof of this is left
to the inclined reader ;-)

> The example used on the page assumed 100GB in use, with 5% change per
> day, and a dump every day in a 7 day cycle.  The example came up with a
> dump size of ~17GB.
> 
> Does anyone know the page of which I speak, or of a similar discussion?
> If so, would you be kind enough to post a link?
> 

Try

http://www.storagemountain.com/amanda-12.html
http://www.storagemountain.com/amanda-17.html
http://www.storagemountain.com/amanda-8.html


-- 
Regards

Chris Karakas
http://www.karakas-online.de