Fusion Drive

[theeaglehasland]

I have a late 2019 iMac and I am currently running Monterey. I replaced the original 3TB Fusion Drive with a 2TB SSD Drive which is running fine. The original 128GB SSD was fused with the new SSD to create one 2.12TB Fusion Drive. I have now received a warning in DriveDX and iStat menu that the original SSD only has 4% life left. I want to avoid the Mac running into problems and would like to split the Fusion Drive and only use the "new" SSD Drive. However, the original 128GB SSD is showing in Disk Utility as having 22.23GB of data on it.

My questions are 1) how can I find out what this data is? 2) Is there a safe way of splitting the Fusion Drive and disabling the original SSD partition? 3) Is there another option? Do I need to be concerned if the original SSD fails if the "new" SSD is working fine?

Many thanks

 

[Fishrrman]

1. Use either CarbonCopyCloner or SuperDuper to back up the contents of the [current] fusion drive to an external drive. Both CCC and SD are FREE to download and use for 30 days, so doing this will cost you nothing.

2. DE-fuse the fusion drive using terminal. Then use disk utility to erase both components of the drive (SSD and HDD).

3. RESTORE from the cloned backup to the 2gb SSD -only-.

4. Leave the internal 128gb Apple SSD "in place, but not used". It will appear on the desktop, you can either eject it or just ignore it.

Personal observation:
I sense that in the days to come we're going to see a lot more posts from users who have problems similar to this one -- that is, a component of the fusion drive failing or completely failed. It's going to leave users in a very precarious position, especially those without backups...

 

[theeaglehasland]

Thanks for this. Is there any way to see what data is on the failing Fusion SSD?

 

[Fishrrman]

"Thanks for this. Is there any way to see what data is on the failing Fusion SSD?"

I doubt that.
If the drive is still running, and you have reason to suspect that it might fail in the future, then get "the whole fusion drive" backed up as a protection against such failure.

When one-half of the fusion drive goes, there's a good chance that it will take all the data with it...