Separate SSD and HDD? Container Disk2 and Container Disk3

RonSkingley

macrumors newbie
Original poster
Feb 18, 2020
6
3
Hello All,
Hope there's some help out there as I'm confused.
I had to do a somewhat convoluted restore from a different OS, using Command R.
It finally got there, and it's taken days to get back all the Logic data and FCPX etc.
But now, when I look at Disk Utility there is Container disk2 and Container Disk3.
Only Container Disk3 has anything in it - MacOS and MacOS - Data.
But....
Container Disk2 says APPLE SSD SM0128
And Container Disk3 says APPLE HDD ST2000

Somehow all this doesn't seem right.

Any ideas?
Screenshot 2020-02-18 at 09.46.05.png
 
Last edited:

barbu

macrumors 6502a
Jul 8, 2013
715
736
wpg.mb.ca
It appears you have a Fusion drive but have inadvertently split the SSD and HDD from the logical disk that unifies them. Right now, you are running entirely on HDD, negating the performance benefit of the SSD.
I would think you'd want to repair (re-pair!) the drives back into a single logical Fusion drive unit. The SSD part of the fusion drive is probably too small to use exclusively as the boot device, but that may be an option depending on your needs. This would be faster than using the HDD and faster than the Fusion configuration, just with much lower space.
 

RonSkingley

macrumors newbie
Original poster
Feb 18, 2020
6
3
It appears you have a Fusion drive but have inadvertently split the SSD and HDD from the logical disk that unifies them. Right now, you are running entirely on HDD, negating the performance benefit of the SSD.
I would think you'd want to repair (re-pair!) the drives back into a single logical Fusion drive unit. The SSD part of the fusion drive is probably too small to use exclusively as the boot device, but that may be an option depending on your needs. This would be faster than using the HDD and faster than the Fusion configuration, just with much lower space.
Thank you Barbu,
Do you know how I might repair them back together?
I have no idea how I managed to separate them.
Could a repair be done without damage to the data (system and data)?
 

Fishrrman

macrumors Core
Feb 20, 2009
19,444
6,741
OP wrote:
"Do you know how I might repair them back together?
I have no idea how I managed to separate them.
Could a repair be done without damage to the data (system and data)?"

You MUST BACK UP ALL YOUR DATA ON BOTH DRIVES BEFORE you attempt to "re-fuse" them. Failure to do so will almost certainly result in the loss of ALL data on the two drives.

The SSD and HDD can be re-fused using terminal, but I've never tried it.
I'm not sure if Disk Utility can do it --- others may provide that info.

If it was me, I'd just leave the SSD and HDD "as separated, stand-alone drives".
This way the SSD will always run at maximum speed.

You DO have to be mindful of what you keep on the SSD.
128 is "on the small side", and although that should be fine for the OS, apps, and very "basic" accounts, your "large libraries" (movies, pics, audio) should be stored on the HDD.
 

Weaselboy

Moderator
Staff member
Jan 23, 2005
30,339
10,103
California
Do you know how I might repair them back together?

Backup your data to an external drive then follow this link to put the Fusion drive back together. Then restore your backup back to the Fusion drive.

Edit: Ninja'd by @nicho :)
 
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RonSkingley

macrumors newbie
Original poster
Feb 18, 2020
6
3
Thanks all for your excellent advice.
I've made a backup, or a clone, using SuperDuper! to an external drive.
I will put it on again tonight to update.

After using the terminal command, I'm hoping to re-install from the external drive.
Do I need to make sure the external drive is NOT bootable to do this?
 

RonSkingley

macrumors newbie
Original poster
Feb 18, 2020
6
3
Ah.
Right.
You don't have to boot from an external drive to restore.
When you do the command+R boot up and select restore, you can select to restore from TimeMachine, or from another external drive.
In this case I would use the backup made using SuperDuper!
But one of the options on SuperDuper! is to make the external drive bootable, rather than, I presume, just a store of all the files.
 

Fishrrman

macrumors Core
Feb 20, 2009
19,444
6,741
OP wrote:
"In this case I would use the backup made using SuperDuper!"

WAIT!
STOP RIGHT THERE!

Do you mean "backup" (singular, one drive) or "backups" (plural, two drives)???

You have to back up BOTH the SSD and HDD drives, because if you only back up one, the data on the other is going to be WIPED OUT.

Just a friendly warning before you start...!
 

RonSkingley

macrumors newbie
Original poster
Feb 18, 2020
6
3
Update.
All done.
The SuperDuper! backup was a bit belt and braces, as I had another external drive that TimeMachine was using.
So did the command+R bootup, ran terminal, typed in diskutil resetFusion, and away it went doing it's stuff.
Then selected restore from Time Machine.
It took about 3 hours, but is now running fine, with Disk Util showing only one container disk, with MacOS and MacOS - Data in it.
And the whole machine is running a lot faster.

Thank you all for your help and guidance.
Ron
 
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