possible to have 2 Time machine "silos" on same machine?

[clay]

I've done some searching and can't find a conclusive answer, so thought I'd ask the knowledgeable folks here a question about Time Machine (something I've just started using in the past week).

Say I have 2 internal disks, DISK A and DISK B. Is it possible to have 2 separate time machine backup disks (i.e. one for each of those drives)? Or can Time Machine only exist on a single volume/disk per machine? In other words:

DISK A uses BACKUP DISK A as a Time Machine volume
and
DISK B uses BACKUP DISK B as a Time Machine volume

This doesn't really seem to be a possibility with what I'm seeing in the Time Machine prefs, but I have been wrong before. I already do at least one standard backup (CCC or SuperDuper) with Disk A and Disk B, but I'd like to add Time Machine into the mix if it's easily possible.

[guitarist]

I think your prerequisite that the data be stored on separate physical backup disks might be making it unnecessarily complicated. If you were storing the data in separate silos (folders, directories, whatever) on the same external drive would it work?

Or is the simple fact of trying to instruct Time Machine to backup a boot drive AND a second drive causing the barrier to doing what you want?

[clay]

no, it's actually a question that comes out of having 2 different-capacity extra drives lying around that would work individually with Disk A and Disk B, but since they're not the same size and aren't big enough on their own to backup both Disk A and Disk B, I'm trying to see if they'd work separately, since that's the only way I could think of to fully utilize both extra disks.

(how's that for a run-on sentence? :-) )

[guitarist]

Ha. It's a classic case of a solution looking for a problem, rather than the other way around.

Here's a possible use for those drives. How about redundant duplicates of your most critical backups, then store them completely offsite. Then bring them home three or four times a year to update, but keep them stored offsite. At work. Or in a safety deposit box. Or a family member's house.

I just started doing that with a few spare hard drives. I send them with my wife, she stores a bare HD in her desk at work, containing an emergency backup of our home computer's most critical data. She works at Microsoft, arguably a more secure location than most residential neighborhoods.

Could a person be so unlucky? You might ask--to need such an emergency backup? In my case, YES. Our house suffered major fire damage in 2006, destroying all my macs, all our computer data wiped out, except what I ran out with on one little laptop. And I was the most backed-up person I know! I had terabytes of secure storage and extra backups! I had every kind of redundant backup you can imagine, EXCEPT an offsite backup. I'm living proof that the most unthinkable misfortune can and does happen, even to the most prepared.

Even the Fire Department personnel I talked to on the scene don't have their home data backed up off site. And those are the most saftey-oriented guys you'll likely meet. Everybody has home computers. Nobody backs up offsite. (very rarely, businesses do, but individuals don't)

I admit, I only refresh that emergency backup about once or twice a year. I expect I'll never use it. But I feel safer knowing it's there.

Sorry to be Johnny Raincloud, there ARE more fun things to do with spare hard drives. But it's worth considering, yeah?

[gabester]

On a related note, is there any way to delete stuff from a time machine backup without going through the time machine interface? I.e. I can't delete things from the Finder or terminal even as root.
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