Unable to merge split Fusion Drive
I have a 2019 21" iMac
--> diskutil resetFusion
Internally-located hardware disk device known to the currently-running macOS:
Rotational (disk1)
Volumes exported by partitions or storage systems hosted on the above device:
APPLE SSD SM0032L Media (disk2s1)
APPLE HDD HTS541010A9E632 (disk3s1)
Your computer must have exactly 1 solid-state and 1 rotational disk drive
iMac 21.5″, macOS 10.14