What to do with the SSD portion of Fusion Drive?

Fravin

macrumors regular
Original poster
Mar 8, 2017
160
88
Rio de Janeiro, Brazil
My iMac (2017 21,5" 4k 560pro) is running from a Raid Array of 2 External 500Gb USB-C SSDs almost 1.100 R/W.

What should i do with the SSD from the Fusion drive?

It's a tinny 32Gb SSD...
 

harriska2

macrumors 65816
Mar 16, 2011
1,113
572
Oregon
We just removed our fusion drive but the ssd portion stays behind. We don’t do anything with it. It’s just too small.
 

Fishrrman

macrumors P6
Feb 20, 2009
17,398
5,635
Just leave the internal fusion drive alone.

STRONG recommendation:
Keep a copy of the OS on the fusion drive that is bootable "to the finder".

You ALWAYS want to have a SECOND bootable drive on a Mac, internal or external.

What happens if someday you find you can't boot from the external RAID?
 

allanmulwee

macrumors newbie
Nov 25, 2017
22
0
Has anyone created an SSD Fusion drive? Also if you put in a 1TB SSD and 1TB Stick you could do a raid.
 

Fravin

macrumors regular
Original poster
Mar 8, 2017
160
88
Rio de Janeiro, Brazil
Has anyone created an SSD Fusion drive? Also if you put in a 1TB SSD and 1TB Stick you could do a raid.
Yep, I have did it.

It's fairly simple coding. You can "fuse" the internal SSD with an USB SSD with you want it doesn't need to be internal.

In terminal do the following:

Diskutil list
Note down the disks you will use to the Fusion. Remember that those disks will be erased, so keep a copy of your stuff. As for example, you have to note the "Disk4" that will appear in the right of the list. You will note down the internal SSD and the external one. So you will have two Disks.

Diskutil erasedisk JHFS+ Bla /dev/disk4
Here we will erase the disks. The point here is to eliminate any garbage partitions from the disks, and set their GPT partitions. Do this for the two ones. "Bla" is the temporary name of the disks. You can enter whatever you want. It doesn't matter.

Diskutil apfs createContainer -main disk0s2 -secondary disk4s2
Here we will Fuse down the drives. Remember to replace the disks number with the ones that you have noted. The main disk will be your Internal SSD, the Secondary, the USB SSD. Beware to include "s2" after the disk number, as this operation needs to be done with partitions, not entire disks. If you have run the second step, your main partitions will be s2.
After the operation is complete, it will give you a new Disk number for the fusion drive. Take a note of it.

Diskutil add volume disk6 APFS Name
Here you will put the Disk created. Remember to Name it as you want. This will be the name of your fusion drive.
Enjoy your brand new Fusion Drive. This drive will be able to boot Mojave and High Sierra with no worries.