A significant portion of the users in our company use Macs, mostly MacBook Pros with a few iMacs and Airs thrown in for good measure. We're running a mixture of 10.6 and 10.7. So far we've been providing USB drives to each employee for use as a Time Machine backup, but that's becoming fairly cumbersome.
After searching around, I'm pretty confident we can centralize this with NAS (QNAP, Drobo, etc.) or a Mac Server running on either a Mini or a Pro. From what I have read, the newer firmware for QNAP (and others) can handle the Netatalk changes that went out with OS 10.7. And obviously Mac Server 10.7 plays nicely with everyone.
The problem is that I can't figure out what kind of system I need to support our employees. I'm certain Time Machine is heavy on disk I/O, but does that mean I should treat it like a database server? e.g. increase my spindle count? Is memory or CPU a constraint at all? Or is it strictly network and disk I/O?
More simply: can one Mac Mini running Server 10.7 handle 12 users performing Time Machine backups? Or can a single Drobo B800fs handle the load? What about a QNAP TS-459U+? Or do I need something beefier?
I guess I'd love to see some information about resource utilization in general. First hand knowledge such as "I'm using a Mac Pro w/8GB RAM and 4x disk RAID-10 array to support 20 people" would be immensely beneficial.
Any advice would be appreciated.