Hello, I'm reinstalling Mac OS Sierra in my iMac 4k with Fusion drive. But I don't know if I have to install it in HDD or SSD in my Fusion Drive and why. Thank you in advance.
iMac 21.5" 4K, macOS 10.14
Because you are seeing Apple HDD and Apple SSD it means that your Fusion drive has been de-fusioned.
This means instead of having a medium-high performance single giant Fusion drive, you now have a tiny (128gb or so) fast performance SSD, and the rest of your 1TB or 2TB (or whatever) drive is now a slow-performance regular hard drive.
Most people would not find this an acceptable situation. Your drive needs to be re-fusioned. You can certainly use it as is and reinstall macOS to your SSD-only, and this may be fine for some people, but not for most.
Fortunately, Apple does have a how-to guide telling you exactly how you can re-fusion the SSD+HDD to get back to a single Fusion drive:
Because you are seeing Apple HDD and Apple SSD it means that your Fusion drive has been de-fusioned.
This means instead of having a medium-high performance single giant Fusion drive, you now have a tiny (128gb or so) fast performance SSD, and the rest of your 1TB or 2TB (or whatever) drive is now a slow-performance regular hard drive.
Most people would not find this an acceptable situation. Your drive needs to be re-fusioned. You can certainly use it as is and reinstall macOS to your SSD-only, and this may be fine for some people, but not for most.
Fortunately, Apple does have a how-to guide telling you exactly how you can re-fusion the SSD+HDD to get back to a single Fusion drive:
Is the Fusion Drive intact here? If so I would only expect to see the Fusion Drive as a destination. I think you may need to rebuild the Fusion Drive.
Because on a Fusion Drive the SSD contains the OS.
SSD
Thank you for your time. Can you tell me why?
Many thanks! I decided to accept OS on my SSD and use HDD as back up and rest of documents on iCloud Drive. Thanks.
Reinstall Mac OS Sierra in HDD or SSD? Thank you.
