Mac mini 2012: Merge two internal drives into one

dylanfromdurham wrote:

I've installed two 500 Gb internal SSDs into my 2012 Mac mini. Each reads as a separate drive. Effectively, the second drive is not much different from an external drive, except the SATA speeds are higher than USB, but it also can't be detached.

Nothing wrong with that, except that a large 1T SSD would have held twice as much and been easier to manage.

I'd rather configure these to be treated as a single drive. How can I do that? This would allow me to store more of my data locally, without moving the home folder off my boot drive.

Sadly macOS has dropped support for RAID setups, plus they were only slightly easier to manage and still required some form of backup.

Alternately, if they can't be configured as a single drive, can I set it up to mirror the boot drive on the second drive, that way if one fails the other is available?

Yes and I concur with D.I. Johnson. At this point the safest and easiest thing to do, is to just use Cloning software like CarbonCopyCloner or SuperDuper and keep a full up to date Clone on the second SSD.

It might be possible to configure the drives as a Fusion drive. That's typically a smallish SSD and a larger HDD combined by the OS logic to appear as a single drive to the user. I'm unsure if it's technically possible with two SSDs. I'm sure others can comment.

If left as two separate drives, there's no reason you can't use the second drive as storage without moving the home folder, just as you would an external drive. You can create and designate a Documents folder on the second drive as your default "Save To" location with most apps that you use. Your Photos and Music Libraries can be configured to live on the second drive as well.

As for mirroring your first drive, that's very doable with a utility like CarbonCopyCloner or Super Duper! You could also use the second drive as a Time Machine backup drive, though its capacity is extremely limited.