To set up a Fusion Drive system on your Mac, you don't need any special software or hardware other than a recent version of OS X Mountain Lion (10.8. 2 or later) and two drives that your Mac must treat as one larger volume.
How to Make a Fusion Drive! (with Pogo – Coding and More)
When Apple updates the operating system and Disk Utility to include mainstream support for a Fusion drive, you'll be able to easily create your own Fusion drive. In the meantime, you can do the same thing using Terminal.
In October 2012, Apple introduced iMacs and Mac minis with a new storage option: the Fusion drive. A Fusion drive is essentially two drives in one. The original contained a 128 GB solid state drive (SSD) and a standard 1 TB or 3 TB platter-based hard drive. The Fusion drive combines the SSD and hard drive into a single volume that the operating system sees as a single drive.
Apple describes the Fusion Drive as a smart drive that dynamically moves the files you use most often to the SSD portion of the volume, ensuring that frequently accessed data is read from the faster portion of the Fusion Drive. Likewise, less frequently accessed data is relegated to the slower, but significantly larger, hard drive portion.
