Is my Fusion Drive Dead

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Is my Fusion Drive Dead

I have a Mac Mini (Late 2014 3.0GHz). As I was using it today it started to behave oddly so I restarted it. I got a few weird errors as it shutdown and then it wouldn't start up again - I got the Apple logo, the progress indicator went around 3/4 of the way and then it powered off.

I rebooted in Recovery Mode and went into the Disk Utility. I ran First Aid on Macintosh HD and got errors saying it couldn't repair. The main one was "unable to bootstrap transaction group: bad mlv.

Is there anything I can do to fix it or is it time to buy a new drive?

I believe I have most things backed up by Time Machine (plus more important stuff is backed up by other means). If I restore from Time Machine, what happens to the installed apps?

Thanks

Posted on Dec 2, 2019 2:20 AM

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Answer 1

den.thed

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92,560 points

Dec 2, 2019 7:42 AM in response to ATJ777

ATJ777 wrote:

I rebooted in Recovery Mode and went into the Disk Utility. I ran First Aid on Macintosh HD and got errors saying it couldn't repair. The main one was "unable to bootstrap transaction group: bad mlv.

Is there anything I can do to fix it or is it time to buy a new drive?

If macOS Recovery can not repair the drive or reinstall macOS, then the drive needs to be replaced. Personally I would install a large SSD instead of another spinning 5400rpm HDD.

I believe I have most things backed up by Time Machine (plus more important stuff is backed up by other means). If I restore from Time Machine, what happens to the installed apps?

Time Machine backs up everything. If you restore from Time Machine, then you should be right back where you left off.

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Answer 2

den.thed

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92,560 points

Dec 2, 2019 4:39 PM in response to ATJ777

Yea the HDD is the week link and I never cared for the Fusion drive.

Best thing I ever did for my Mac Mini's, was to pull out those slow, hot running HDD's and replace them with fast, cool running SSD's.

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Answer 3

ATJ777 Author

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Dec 3, 2019 9:12 PM in response to ATJ777

I think I found a solution: https://apple.stackexchange.com/questions/339324/this-disk-does-not-have-enough-space-to-restore-your-system

This is what was listed for my last backup

com.apple.backupd.VolumeBytesUsed: 2092909846528

I changed it to

com.apple.backupd.VolumeBytesUsed: 1900000000000

and now it allows me to restore.

Hopefully it will restore successfully!

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Answer 4

ATJ777 Author

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11 points

Dec 2, 2019 4:18 PM in response to ATJ777

OK.. weird. I thought I would give it another go.

I booted into Single-User Mode and ran:

/sbin/fsck -fy

It checked various things an at the end it said:

** The volume Macintosh HD appears to be OK.

I did not get ***** FILE SYSTEM WAS MODIFIED *****

But I still can't boot.

Also in Single-User Mode I can see the contents of Machintosh HD...

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Answer 5

ATJ777 Author

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Dec 2, 2019 12:28 PM in response to den.thed

Thanks!

Reinstalling MacOS doesn't appear to be an option as I can't mount the drive.

I think I will replace with a 2TB SSD.

I had some exceptions configured into Time Machine (large number of large files that I backup another way) so in my case it won't restore everything. I just can't remember all the exclusions. I guess I will find out on restore.

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Answer 6

den.thed

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92,560 points

Dec 2, 2019 12:52 PM in response to ATJ777

ATJ777 wrote:

Thanks!

You're welcome!

I had some exceptions configured into Time Machine (large number of large files that I backup another way) so in my case it won't restore everything. I just can't remember all the exclusions. I guess I will find out on restore.

Yea, restore from Time Machine and then go on a scavenger hunt for the excluded items.

The other option, provided that your Time Machine drive has enough space. Is to include those items into the next few backups before you migrate.

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Answer 7

den.thed

Level 10

92,560 points

Dec 2, 2019 4:30 PM in response to ATJ777

Good idea! I'm running SATA SSD's in several Mac Mini's and they all run Mojave and Catalina very well.

You could run non-fusion with both SSD's, macOS on the blade SSD and everything else on the SATA SSD, but then that tends complicates, backup, updates and future upgrades.

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Answer 8

ATJ777 Author

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Dec 3, 2019 8:03 PM in response to den.thed

ARGH!

I bought a 2TB OWC Mercury ELECTRA 6G 2.5" 7mm SSD. I replaced the drive without too much trouble.

I started up the system with the Option key pressed and told it to boot from my Time Machine disk but that failed.

I did an Internet Recovery Mode and got it to boot. I used Disk Utility to partition the new drive but it shows as only 1.92TB rather than 2TB.

When I attempt to restore from Time Machine and select the newly created partition I get a message saying "This disk does not have enough space to restore your system"!

What are my options?

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Answer 9

ATJ777 Author

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Dec 3, 2019 8:14 PM in response to ATJ777

I should add that my Time Machine drive is 2TB with 1.97TB used (25.72GB free). It has been used for multiple backups since February so there is no where there is even 1TB of data backed up to it.

While my original drive only had around 100GB free, I had excluded over 1TB of data that I was backing up separately and didn't need in Time Machine.

From searching on the 'net it appears this is a common issue with having exclusions with Time Machine but I haven't yet found any answers.

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Answer 10

ATJ777 Author

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Dec 4, 2019 2:09 AM in response to ATJ777

The restore took just under 2 hours to restore around 280GB (not 2TB as Time Machine thought). Everything seems to be in place. Some settings weren't remembered but generally it looks fine. My Photos library was rebuilt and now it is "uploading" everything to iCloud, even though it was already there.

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Answer 11

den.thed

Level 10

92,560 points

Dec 4, 2019 8:20 AM in response to ATJ777

Yea' it used to be easier replacing a drive and restoring in the earlier macOS versions. Sorry for not being able to respond back to your earlier posts. But I am glad to hear that you sorted it out, by Install macOS and then Migrated from your Time Machine backup.

Good work, enjoy!

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Answer 12

ATJ777 Author

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Dec 4, 2019 11:38 AM in response to den.thed

Actually I am on an earlier MacOS version - Sierra. I need to stay on this due to some software compatibilities.

Also, I didn't need to install macOS first. It was just that I couldn't boot from the Time Machine drive. I had to boot in Internet Recovery Mode and then restore from Time Machibe (but only after changing the reported size of the Time Machine backup which was completely wrong).

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Answer 13

ATJ777 Author

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11 points

Dec 2, 2019 3:31 PM in response to den.thed

Thanks, again!

If I'm going to replace with a 2TB SSD, can I remove the current SSD blade at the same time? i.e. I don't want to run Fusion any more.

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Answer 14

den.thed

Level 10

92,560 points

Dec 4, 2019 2:22 PM in response to ATJ777

Ah... yes, because the Time Machine drive was full. Personally I never tried starting up from Time Machine.

When I replace a drive, I use one of two methods.

use Recovery to Format and Install macOS, then Migrate from Time Machine or a Clone.
use Recovery to Format and then Restore from the original drive (if working) or a Clone.

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Is my Fusion Drive Dead

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