I'm hoping someone has had experience with this and can offer some advice, here's the lowdown on my scenario.
I have a Mac Pro tower (so 4 drive bays) with all bays filled.
- Bay 1 has a 320GB HDD hosting Mavericks
- Bay 2 has a 1.5TB HDD JHFS+ formattedd for a data/archive disk
- Bay 3 has a 320GB HDD hosting Windows 7
- Bay 4 has a 120GB SSD that I just installed macOS Sierra on.
I have a 2TB external HDD that I use for Time Machine backups, and in the past I backed up disks 1 and 2, leaving the Windows disk alone, of course. Now that I have an SSD running Sierra, my goal is to use Sierra as my primary OS, and only use Mavericks when necessary. (And it is necessary, occasionally.)
Ultimately my concern is this: I do not need Time Machine trying to back up three disks to my backup disk from one OS, only to have it attempt to do the whole thing over again when I boot into the other OS. Is Time Machine intelligent enough to know that I am backing up the same three disks from two OS's?
Update: I ran Time Machine from the Sierra disk and it didn't try to duplicate the backup of the storage disk, so that's half of my question answered at least, but I'm still not sure I want to boot into Mavericks with the Time Machine disk connected until I know what to expect from it.