> I'm trying to calculate what our new backup window would be if we went
> from LTO1 to LTO2 tape drives. 

If the tape drives were not the bottleneck, your backup window will not 
change at all.  You need to do some extensive calculations and research 
to see where the bottlenecks currently are.  It's also possible that the 
tape drives are only part of the bottleneck and not all of it so one 
possible outcome is that you may only go a little bit faster before you 
hit the next bottleneck.

I've seen quite a few cases where the clients are the bottleneck.  We 
could move them to disk-based backups but the window wouldn't change.

It's a tough, tough problem...

-- 
Ed Wilts, Mounds View, MN, USA
mailto:ewilts AT ewilts DOT org