Hi all, sorry if this is a bit too simple but is it possible to boot an MBP running 10.6.8 from an external RAID hard drive?

I currently have a 120 (128?) gig SSD as a boot drive and a 750 gig SATA HDD as storage in my MBP. I was thinking of setting up an external RAID with a partition for the SSD's duplicate and the other partition as a Time Machine backup for versioned backups.

Thanks!

There are no simple questions. Only redundant stupid questions.

Are you having a bad day?

what do you want the RAID to achieve?

It sounds like you want to set them up in a RAID level 1 - two drives with the same data on each drive. the primary purpose of this setup is increased uptime. after all, you could achieve the same thing with a nightly carbon copy cloner or super duper setup. also, i suspect you'd lose the speed benefit of your SSD....but it would be external so maybe it wouldn't matter.

I dunno, kinda sounds like a franken-RAID.

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Thanks for the request for more clarification. I am just reading through Taking Control's Backup e-book and Kissel was recommending a backup of your backup.

So, yes, I could do the above with SD on to a larger external HD but was thinking would it be better to go with a RAID 1 solution? Of course, this lead to my question of whether or not a RAID is bootable?

Well, I put in a quick online chat with OWC and, yes, it is bootable.

It's bootable, but why the HELL would you do it?!

I don't quite understand the question, admittedly. Do you want to leave your internal drives as-is and create a RAID 0 external that will house two partitions, a copy of the SSD and a Time Machine partition? I don't understand why you want RAID for this? There's little-to-no advantage of the speed RAID 0 gives you with backups. It DOES give you the advantage of a single, larger drive given the two drives' capacities are combined, but you're not really getting more "space." RAID 1 doesn't make sense to me either as you've then got 3 copies of your data but only in 2 places, so you haven't actually increased your likelihood of protecting data by making three separate, independent copies (RAID in a backup scheme, even if it's redundant RAID, can only be counted as one backup within the scheme given my next point...).

With a RAID array being the only "backup" in your backup scheme you're betting your entire backup on a RAID array not failing. The minute your array has a hiccup you loose EVERY backup you've got (both versioned, a la Time Machine, and current-state a la the SSD's duplicate).

So while, yes, it's bootable, I would NOT recommend a RAID array in your backup unless it's a RAID 5 or RAID 1+0 that's your THIRD, independent backup (meaning you have an orginal on the machine, a second backup on a separate drive, and then the RAID array as your third, possibly off-site, backup) or a RAID 0 that's ALSO backed-up onto a third location (like a large 3TB drive that houses the entire contents and updated weekly and stored off-site).

I think you're asking for trouble and I see little to no benefit of using RAID in a backup scheme for 99% of users.

~A

tahoe, thanks for the input. Still trying to wrap my head around all of this.

I agree that having a backup of your backup is a good idea but I think you're being too literal. You just need multiple backups.

I recommend Time Machine, SuperDuper/CCC, and BackBlaze (or something similar)

Those three offer a lot more than a RAID 1 setup -

Time Machine
- revisioned backups

SuperDuper/CCC
- Bootable backup

BackBlaze
- Offsite backup

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Thanks mattkime, I'm probably overthinking this.

I once briefly thought about using a RAID 1 for a back-up so that I could pull one of the drives to use as an off-site back-up. But since I couldn't find an enclosure that could easily re-sync the drive (it would want to do a complete copy of the remaining drive to any newly inserted drive), it became more trouble and time-consuming than it was worth.

I just rotate drives now, one off-site and one on-site and use Backblaze as well. So each of my physical drives is missing a week or so of revisions when it is off-site, but that's fine for my purposes.

Thanks Gareth for the input; I do know that some people such as OWC Jamie uses RAID 1 as part of their backup strategy. At the rate I am going, RAID 1 is looking less like a possibility and I may end up with just another stack of fatter external HDs.