Mac OS forum


Can Mac OS X install/run on a RAID?

by Pixelmage / July 5, 2012 1:35 AM PDT

I have a iMac 3.4 GHZ with 16 GB of memory, SSD boot drive and 2TB internal. I want to attach a RAID to it (OWC Mercury Elite Pro Qx2, eSATA, FireWire 800+USB).

Is it possible to install Mac OS X on a RAID? If so, what Mac OS X version would work best (Snow Leopard? Lion?) and what RAID level would be appropriate (I am debating between level 5 or 10).

I figure if my iMac went down I can plug and play and boot up with the RAID on another computer.

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All Answers

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I used google and
by R. Proffitt Forum moderator / July 5, 2012 1:44 AM PDT

It appears it can.

As to what RAID level, that depends on what you are looking for. We know that RAID is not going to save our files (some still believe it will!) but only you can pick which one.

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It can
by Jimmy Greystone / July 5, 2012 1:26 PM PDT

It can do RAID 0 (technically not RAID) and RAID 1 in software, everything else requires dedicated RAID hardware.

I would have to say that you seem to be overthinking this by a significant margin. It's one thing to have a backup drive that's bootable, but making that a RAID would be considerable overkill. If the internal drive(s) go out and you lose access to the OS, then the idea would be more to have something to help you limp along while you get the drive(s) replaced. What you're proposing is serious overkill.

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OS X from RAID works
by mr645 / July 6, 2012 10:28 PM PDT

Yes, OS X can boot from RAID 0 or RAID 1. RAID 0 works very well to speed things up, but you loose reliability with having the chance for any of the drives in the array to fail. Back up is important in this case.

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RAID yes, RAID 5 iMac? No
by mr645 / July 6, 2012 10:33 PM PDT

I don't think you can setup a RAID 5 with an iMac without some type of external RAID system. You should be able to do RAID 10 with 4 external drives. I have never tried it but you could first make two sets of RAID 0 arrays and then try mirroring them together. For RAID 5/6 you need some type of a controller, such as one of the Highpoint cards, but you need a tower to install the card into. Also, with drives of different speeds, RAID performance can suffer. In your case, I would just suggest booting from the SSDm storing data on the 2TB drive, and using something like CCC to back up everything to the external drive.

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