How does Time Machine deal with multiple drives?

Hi. I'm close to purchasing a new 27" iMac. Just sorting out the details. My one concern is regarding backups. I would be getting the iMac with 256gb SSD and 2gb 7200 rpm data drive. OSX would be installed on the SSD, and my data would be stored on the other drive. However, from what I have read about Time Machine, there isn't much you can configure. It basically asks "what drive?" and then backs up that whole drive. Is there any way it could be configured to backup both drives? Realistically, I wouldn't need daily backups of the system drive, but if it's incremental, it wouldn't likely be a problem. Do I basically have to run two backup software packages (e.g. Time Machine for system drive and something else for the other drive)?

The up and coming Mountain Lion (end of this Summer) will take care of that. The new Time Machine application will be able to handle multiple drives according to an article in this month's Mac World magazine. However, until then, you'll need to designate two separate drives and perform two separate backups. Of course you can always use one large external hard drive partitioned into two naming them Time Machine 1 and Time Machine 2 or some such. Not elegant, but until Mountain Lion comes, should suffice.

ok... so Time Machine needs its own special partition for the backup? If I have a large external raid setup, how would I configure Time Machine to backup to it (without losing all the space)? Do I just figure out what the maximum size the backup could be, and allocate that much to a partition, or does Time Machine somehow allocate what it needs?

The reason for my question is that I haven't decided what to use for backups, yet. If I could scrounge up enough cash, I was pondering one of those over priced multi-drive Promise Pegasus Thunderbolt units. I'm a software developer, and this would give me lots of space to store all my libraries, graphics, etc. in a raid protected environment. It would make the idea more viable if I could also have my backups stored there. Maybe that's not possible, though. What types of hardware/environments is Time Machine compatible with?

Awesome that it will work better in Mountain Lion.

chscag said:

... naming them Time Machine 1 and Time Machine 2 or some such.

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You can have multiple Time Machine configs? I was looking at Time Machine on a demo in the store, so I couldn't actually trying setting it up, but it looked you could just configure it for one drive. Does it allow you to configure a second one after you have the first setup?

You would configure each hard drive that needed to be backed up separately; that's what I meant by partitioning one large drive into two partitions. Hard drive 1 backs up to the partition named Time Machine 1 and so on. Of course you can name them whatever you choose. The point being that you would have to run Time Machine twice for each backup session. Once for each hard drive.

You might even prefer using a third party backup program instead of Time Machine. One that could handle multiple drives, at least until Mountain Lion is released and you upgrade.

A review of Mac backup software: LINK

Chscag, I noticed Carbon Copy Cloner is not in that list! Interesting as it's an excellent application .

chscag said:

You would configure each hard drive that needed to be backed up separately; that's what I meant by partitioning one large drive into two partitions. Hard drive 1 backs up to the partition named Time Machine 1 and so on. Of course you can name them whatever you choose. The point being that you would have to run Time Machine twice for each backup session. Once for each hard drive.

You might even prefer using a third party backup program instead of Time Machine. One that could handle multiple drives, at least until Mountain Lion is released and you upgrade.

A review of Mac backup software: LINK

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Ya, I understood the two destination partitions. However, what I was wondering is how to actually initiate the Time Machine copy. i.e. would it run all the time or scheduled doing an incremental backup, or would I be manually initiating full backups and specifying each drive every time.

Thanks for the link. I should be able to find something that will work.

I'm not sure, but I don't think that you can setup Time Machine to do automatic backups on both hard drives. You'll likely wind up doing it manually which may not be something you'll want to do.

chscag said:

I'm not sure, but I don't think that you can setup Time Machine to do automatic backups on both hard drives. You'll likely wind up doing it manually which may not be something you'll want to do.

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I've been doing some more reading on a variety of forums and one of the more common scenarios seems to be having Time Machine running continuous incremental backups of the system drive, and then having SuperDuper creating backups of the data drive. It sounds like it would work quite well.

That would work. My personal backup regimen consists of using both Time Machine and Carbon Copy Cloner (similar to SuperDuper) to two different external hard drives. I do my backups manually though.

SuperDuper or Carbon Copy Cloner can be scheduled to do incremental backups subsequent to a full backup. Time Machine's first backup is full. Afterwhich it will do incremental backups.

If I am not mistaken, Time Machine backs up al drives except the on TM puts it's backups, network drives and all drives/folder explicitly excluded via the TM settings.

I have 2 external 2TB drives on my iMac with Lion 10.7.3: one for data, one for TM. The internal HDD, and the external data HDD both get backed up to the TM external HDD.

Thymen

Thymen said:

I have 2 external 2TB drives on my iMac with Lion 10.7.3: one for data, one for TM. The internal HDD, and the external data HDD both get backed up to the TM external HDD.

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Thanks, Thymen. Can you explain to me what needs to be done to set up a drive for TM to backup to? Does it have to be separate drive with nothing else on it, or can you create a partition on a drive for TM backups to be stored? Do you just guess at your backup size and make a partition at least that big? What about a RAID array of several drives? Is there a way for TM to backup to that, but still have unused space available for other things? Sorry for the barrage of questions. TimeMachine is the one thing I can't actually try out in the store.

dtravis7 said:

Chscag, I noticed Carbon Copy Cloner is not in that list! Interesting as it's an excellent application .

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I noticed that too Dennis. MacWorld consistently rates CCC over SuperDuper for cloning and backups. I use CCC and have been using it ever since Leopard.

Lastmboy said:

Thanks, Thymen. Can you explain to me what needs to be done to set up a drive for TM to backup to? .

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In my reply I stated that I have two external drives; one 2TB drive is for TM only, and in the TM preferences I have designated the drive as such. All other drives, except network volumes and removable media get backed-up automatically, unless you have specified explicitely what drives/folders to be excluded
I have LightRoom, which created a 500 MB database, and a 200GB preview-catalog on my internal disk that get modified often. Backing up these would mean excessively large backups, so I have exluded these.

Thymen