I have a 3 Tb fusion drive and disk utility thinks it is only 257 Gb

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I have a 3 Tb fusion drive and disk utility thinks it is only 257 Gb

I have a 3 Tb fusion drive. Disk utility thinks the capacity is 256 Gb. I need to add 2 more partitions. I can't partition it. I think that I've fixed this problem before by erasing the entire physical drive. But the "Erase" button is gray. Note that "Size" is 3 Tb. Note that the "+" & "-" buttons are gray. I've done this many times before. Why does it not work this time? I'm running OS X 10.12 on a 27" iMac. (Please don't ask why I partition my drive. I have very good reasons. Please don't tell me that I can't partition a fusion drive. I have done it many times before.)

27" iMac

Posted on Dec 1, 2018 7:16 AM

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Answer 1

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required desired alias Author

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Dec 2, 2018 4:27 AM in response to required desired alias

I fixed it. The solution is here: How to fix a split Fusion Drive - Apple Support. Somehow, my computer had forgotten that the two physical drives, the SSD and the hard drive, should be a single logical volume. Disk Utility can't fix that. Disk Utility doesn't even know that is the problem. I had to go down into UNIX to create the single logical volume. And then I successfully partitioned the fusion drive.

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Answer 2

Dec 1, 2018 9:24 AM in response to required desired alias

I've made some progress. Booting from Mojave, I got disk utility to recognize that my drive is 3 Tb. But now, whilst trying to resize the boot partition, I'm looking at a spinning beach ball for hours.

Is anything really happening or is it hung? What is "growing disk" anyway.

It says Disk Utility is not responding, but that doesn't necessarily mean the system is hung. I get that sometimes with a lot of disk I/O. How long should I wait? How long is "a while"?

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