FYI: Tahoe does not support Fusion Drives

[venom600]

TLDR: Tahoe no longer has support for fusion drives, even if it is external.

A few years ago I bought a Seagate Firecuda thunderbolt dock. It has a 4TB HD in it, and space for an M.2 SSD. I installed a 1TB SSD and had the brilliant idea to make them into a fusion drive since they are in one unit that can't be separated. Never had an issue, performs well, forgot it was even a fusion drive. Then I upgraded to Tahoe and all of a sudden the drive was no where to be found. I checked disk utility and there were the two individual drives, unlinked.

I did some research and couldn't figure out what was wrong, but I had some data on the drive I didn't want to lose and there's no way I could find to reconnect the drives once the fusion has been broken. So in a panic I think that maybe it's a Tahoe issue, as I was reading that fusion drive Macs aren't supported anymore. I install Sequoia and there it is. I don't seem to remember hearing anything about them removing support for fusion drives specifically, but maybe that's just because no one is crazy enough to do what I did.

 

[!!!]

That's insane that Apple didn't mention it anywhere, didn't provide any deprecation notices, and didn't give you any kind of error when you plugged in a Fusion drive. Apple has gone downhill, and fast.

 

[Bigwaff]

Fusion Drives haven't been a thing for over half a decade. No Mac which natively supports Tahoe ever shipped with Fusion Drives. Lack of Fusion Drive support in Tahoe has been known since WWDC. It's a challenge for the OCLP community and will bite quite a few foolios who attempt to install Tahoe on their unsupported iMacs. As @venom600 admitted, he done did something wacky.

 

[Arran]

Oh crap. Just last week I dug out an old fusion drive I'd completely forgotten about.

Updated to Tahoe today. I guess I'll bury it again.

 

[venom600]

Lack of Fusion Drive support in Tahoe has been known since WWDC.

Yeah, I fully own that I was using it in an unsupported way and I'm not blaming anyone for this but myself. Just wanted to make sure that anyone else that did this would be aware.

Did they specifically call out a lack of support for all fusion drives, or a lack of support for macs that shipped with them? I knew that they weren't supporting the machines that shipped with them anymore, but that doesn't necessarily mean they would drop support for the drives entirely, and I could find no mention of that anywhere. Of course, since they were never supposed to be used on external drives I guess I understand why.

 

[Darth.Titan]

My M2 Mac mini has an external Fusion Drive in a Thunderbolt JBOD enclosure. I updated to Tahoe on day 1.
The Fusion Drive functions just as it did before the update.
As far as I can tell Tahoe supports Fusion drives just fine.

 

[Arran]

My M2 Mac mini has an external Fusion Drive in a Thunderbolt JBOD enclosure. I updated to Tahoe on day 1.
The Fusion Drive functions just as it did before the update.

Excellent, thanks. I'm in a kind-of similar position (USB C 3.1 external enclosure, not thunderbolt).

I was sort-of wondering how the drive type (fusion) would even be visible to the Mac. I was going to try it out tomorrow just for fun.

I'll check that task off my list for now.

 

[Bigwaff]

My M2 Mac mini has an external Fusion Drive in a Thunderbolt JBOD enclosure.

I don’t understand how this is possible. Please elaborate.

 

[Darth.Titan]

I don’t understand how this is possible. Please elaborate.

I use an external thunderbolt enclosure that has 4 SATA drive bays. One bay has an 8TB drive, the next has a 1 TB ssd. I created a Fusion Drive from those two drives to try to make the slower spinning HD a bit speedier.
For the record I currently have 2 1 TB SSDs in the other two bays striped together for fast data storage.

 

[Bigwaff]

I use an external thunderbolt enclosure that has 4 SATA drive bays. One bay has an 8TB drive, the next has a 1 TB ssd. I created a Fusion Drive from those two drives to try to make the slower spinning HD a bit speedier.
For the record I currently have 2 1 TB SSDs in the other two bays striped together for fast data storage.

This really piques my interest. Since you have 2x drives paired as Fusion Drive and 2x 1TB drives "striped together" (I assume RAID-0), I assume the enclosure is not in JBOD mode or any hardware-based RAID mode. This implies software-based RAID? Can you share the make and model of the Thunderbolt enclosure and RAID software?

 

[Batt4Christ]

Fusion Drives haven't been a thing for over half a decade. No Mac which natively supports Tahoe ever shipped with Fusion Drives. Lack of Fusion Drive support in Tahoe has been known since WWDC. It's a challenge for the OCLP community and will bite quite a few foolios who attempt to install Tahoe on their unsupported iMacs. As @venom600 admitted, he done did something wacky.

"for over half a decade"... as in 5 years? Despite many SUPPORTED (newest OS) Macs out there that are 5+ years old? Really?

 

[Bigwaff]

"for over half a decade"... as in 5 years? Despite many SUPPORTED (newest OS) Macs out there that are 5+ years old? Really?

Last models to offer Fusion Drive configuration were 2014 Intel Mac mini (sold until 2018) and... I guess this is where your sarcasm rings true... 2019 Intel iMac 4K 21.5 (sold until 2021). So I stand corrected... because of this low-end iMac configuration, it hasn't really been 5+ years. Where your sarcasm rings false.. these Fusion Drive configured Macs do not support macOS 26 Tahoe (newest OS).. and, of the Apple Silicon or Intel Macs which do support macOS 26 Tahoe, not a single one offered a Fusion Drive as a configured option. Apple has no reason to support Fusion Drives in macOS 26 .. which is really the crux of this thread.