I've got a Mac Pro that I use as, among other things, a Time Machine server. This is currently backing up three machines, including itself. Can I install two disks into the server and have Time Machine back up some clients onto Disk A and some clients onto Disk B? I'm not looking for redundancy (which I know I can now get with multiple Time Machine disks in 10.8); I'm just trying to spread the single backups across multiple disks. Any advice out there?
Yes - assuming you have OS X server running on the Mac Pro, you could share each drive under a different name and enable both for Time Machine backups.
You could then configure some portion of the machines to hit share A and the rest to hit share B. Since each computer stores backup contents in a sparse disk bundle, you could even shift a backup or two to the other drive and then reconfigure things if your initial allocation wasn't working after some time passes.