Fusion Drive. A single drive?

[iHateMacs]

Is my 3TB fusion drive an all in one drive that contains a HDD and a SSD or is it only "one drive" because the iMac treats a 3TB HDD and a 128GB SSD as one drive but in reality they are separate devices?

 

[jqworle]

It's just one drive

 

[marzer]

Is my 3TB fusion drive an all in one drive that contains a HDD and a SSD or is it only "one drive" because the iMac treats a 3TB HDD and a 128GB SSD as one drive but in reality they are separate devices?

The latter. A fusion drive is made up of two devices, a 128GB SSD and a 3TB HDD. The operating system (a subsystem known as corestorage) creates a single logical volume from the two physical devices.

 

[iHateMacs]

The latter. A fusion drive is made up of two devices, a 128GB SSD and a 3TB HDD. The operating system (a subsystem known as corestorage) creates a single logical volume from the two physical devices.

Thank you.

 

[vga4life]

The latter. A fusion drive is made up of two devices, a 128GB SSD and a 3TB HDD. The operating system (a subsystem known as corestorage) creates a single logical volume from the two physical devices.

Yep, this - and I'd also note that it is possible to split the fusion drive into 2 separate volumes if you're so inclined.

http://www.macworld.com/article/2015664/how-to-split-up-a-fusion-drive.html

 

[marzer]

Yep, this - and I'd also note that it is possible to split the fusion drive into 2 separate volumes if you're so inclined.

http://www.macworld.com/article/2015664/how-to-split-up-a-fusion-drive.html

Yup. That simply deletes the corestorage logical volume leaving the drives addressable as two separate physical devices.

For some Fusion "fun" 😀, follow the discussion in this thread. I've added multiple partitions (beyond the 2 permitted by the GUI version of Disk Utilty) or resized partitions in a Fusion configuration without losing the existing data.