Faking Fusion on OS X

CoreStorage Logical Volumes Backed by Multiple Physical Volumes

Here are some articles that helped me setup a DIY Fusion Drive, like the ones shipped in Apple’s latest desktop Macs, in an older Mac Mini. You’ll need a Mac with an SSD and HDD. I put together this setup using a Mid 2011 Mac Mini and an SSD and Data Double Kit from OWC. The HDD I used is the one that my mini shipped with.

The short story is, the Core Storage diskutil commands as well as any hardware mods you make are not supported by Apple. (Try this at your own risk!) You’ll need to wipe all the data on both drives to create the logical volume. While I’ve found this setup very stable for the past three months that I’ve been using it, I haven’t exceeded the capacity of the SSD, so I don’t know what kind of performance penalties you run into when a Fussion drive gets closer to full.

Example DIY FusionDrive setup with test results

DIY FusionDrive writeup

The Commands:

Create the logical disk. Use the list commend to find the Logical Volume Group (LVG-UUID). Finally create the volume using all available space.

diskutil coreStorage create CoreStore disk1 disk2
diskutil coreStorage list
diskutil cs createVolume {LVG-UUID} jhfs+ "CoreStore" 100%