Split Fusion drive and disable failed drive

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Level 1

38 points

Split Fusion drive and disable failed drive

So I have a Late 2012 iMac 27" with a 1 TB fusion drive. Naturally the spinning drive has now failed and the mac won't boot off the fusion drive. Running on my USB 3.0 external drive for now.

I think ultimately for reliability i'm not going to replace the spinning drive and i'm going to go with a external SSD thunderbolt raid. But, how can I go about doing a couple of things...

1 - split the fusion drive into 2 disks so that I can format and actually use the SSD which is still fine.

2 - completely disable the spinning drive which has failed so the OS quits trying to spin it up and detect it and always telling me it has failed etc.

iMac (27-inch, Late 2012), Mac OS X (10.7.5)

Posted on Jul 13, 2016 7:50 AM

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Answer 1

Garrett Howe Author

Level 1

38 points

Jul 13, 2016 7:52 AM in response to Garrett Howe

Naturally i'm trying not to open the computer and disconnect the drive. Yes I have the skills to do that, I just don't want to. Hence why i'm gonna spend more $ and get the external thunderbolt raid.

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Answer 2

Jul 13, 2016 1:33 PM in response to Garrett Howe

You can use this guide to split your Fusion drive into two separate drives:

Split Your Fusion Drive Apart

As for disabling the hard drive, I don't know of anyway to do that other then opening the iMac up and disconnecting the SATA cable.

Tom

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Answer 3

Garrett Howe Author

Level 1

38 points

Jul 13, 2016 1:36 PM in response to Garrett Howe

Strange... now that I have split the fusion drive into 2 separate drives they don't seem to be freaking out. Both disk's say they are "ok" and that smart checks all pass....

Has anyone ever seen a fusion volume just loose it and essentially not work and behave like a failing hard drive but, was ultimately a software problem and not a hardware one?

Wonder if the fusion drive would work again if I rebuilt the fusion drive now that it's split. Gonna try doing a secure erase on the spinning disk and see if it will write 1/0's to the whole thing and not freak out or if the erase fails.

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Answer 4

Garrett Howe Author

Level 1

38 points

Jul 13, 2016 2:03 PM in response to Garrett Howe

Yea no it's dead, it bombed out on the erase with some kinda error. That drive is clearly toast.

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