My 2 TB Fusion drive has become a SATA Drive of 2 TB. I have an IMac 27 inch late 2015 with a 2 TB Fusion drive. After an update my computer crashed. I had to install the OS X from the OS that came with the IMac. I have updated everything to OS Catalina 10.15.7 and i use the Time machine back up to restore. But when i started the IMac i noticed that everything was soo slow.. `everything works slow. Opening apps, opening windows...slow. And then i noticed that my Fusion drive was a SATA drive! If u go to about this mac and then go to 'storage'. then u see that it is an SATA drive instead of Fusion. What can be happened? Is this why my. machine is so slow? Does the IMac not see the Fusion drive?
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IMac 27 inch Late 2015, my 2 TB Fusion drive is now a 2 TB SATA drive
- Thread starter cube42
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Looks like your [previously] "fused" drive got UN-fused in "the crash".
That is, it is now "in two parts":
- the 128gb SSD portion
and
- the 2tb HDD portion
And... your "restore" got put onto the 2tb HDD portion (which of course is a platter-based HDD and is slower).
What I think you need to do is:
1. BACK UP the 2tb HDD to an EXTERNAL backup (time machine or CarbonCopyCloner or SuperDuper).
2. Boot to INTERNET recovery (command-OPTION-R at boot)
3. Open disk utility (make sure you go to the view menu and choose "show all devices")
4. RE-fuse the SSD and HDD back into a "fusion drive" (I'm thinking that disk utility MIGHT be able to do this, or else use the terminal).
5. Now, install a clean copy of the OS onto the re-fused drive.
6. Once done, run through setup assistant and use it to restore your data from the backup.
That's my guess as to what went wrong and how to fix it.
I could be wrong.
That is, it is now "in two parts":
- the 128gb SSD portion
and
- the 2tb HDD portion
And... your "restore" got put onto the 2tb HDD portion (which of course is a platter-based HDD and is slower).
What I think you need to do is:
1. BACK UP the 2tb HDD to an EXTERNAL backup (time machine or CarbonCopyCloner or SuperDuper).
2. Boot to INTERNET recovery (command-OPTION-R at boot)
3. Open disk utility (make sure you go to the view menu and choose "show all devices")
4. RE-fuse the SSD and HDD back into a "fusion drive" (I'm thinking that disk utility MIGHT be able to do this, or else use the terminal).
5. Now, install a clean copy of the OS onto the re-fused drive.
6. Once done, run through setup assistant and use it to restore your data from the backup.
That's my guess as to what went wrong and how to fix it.
I could be wrong.
I agree with @Fishrrman that you no longer have a Fusion drive. One can see from the 'diskutiil list' output that disk0s2 (121 GB) isn't being used for anything. Since you are running from just the HDD, it makes sense that response time is slower.
I also agree with his proposed steps. This apple page give instructions on fixing the Fusion drive:
I notice the instructions say to use Command-R. I'd be surprised if that works because I believe that boots to the internal Recovery partition, which must be destroyed during the 'diskutil resetFusion' command. I'd expect you to need to use Internet Recovery (cmd-option-R) to rebuild the Fusion drive.
Remember, the 'diskutil resetFusion' will delete all the data on the 2TB HDD!
I also agree with his proposed steps. This apple page give instructions on fixing the Fusion drive:
I notice the instructions say to use Command-R. I'd be surprised if that works because I believe that boots to the internal Recovery partition, which must be destroyed during the 'diskutil resetFusion' command. I'd expect you to need to use Internet Recovery (cmd-option-R) to rebuild the Fusion drive.
Remember, the 'diskutil resetFusion' will delete all the data on the 2TB HDD!