Apple Fusion Drive
Fusion Drive is a storage option available on some Mac systems.
Fusion Drive is a hybrid storage solution that combines the performance of Flash storage with the capacity of a traditional hard drive.
Fusion Drive, which appears as a single volume on your Mac, dynamically moves frequently used files to Flash storage for faster access, while infrequently used items are moved to the high-capacity hard disk. As a result of the system learning how you operate, you benefit from faster application launches and file access.
Due to the fact that the data is divided across two hard drives, this is referred to as a Hybrid RAID system. If the Fushion Drive becomes corrupted, the Solid State Drive (SSD) and the Hard Disk Drive (HDD) must be sent to a data recovery center for recovery. This ensures that the data can be restored using the data structure that existed originally (Files and Folders).