Give each drive one partition and set it to have a GUID partition table.ДЇind the hardware identifier labels for both the first (main) drive, and the partition/volume on the remaining drives to combined in the CoreStorage volume. Apply these changes and perform this action for each drive you are going to include in the hybrid drive. Then click the 'Options' button and be sure GUID is selected as the partition format to use. Open Disk Utility in OS X, followed by selecting the drive device (listed above the volume name) and using the Partition tab that appears to select one partition for the drive. Format the drives with a GUID partition table and one partition.Internal drives are preferred for the most stable results and will be required for best Fusion Drive performance, but external drives can also be used. To create a spanned volume with CoreStorage, you will need two storage drives (ensure one is an SSD for Fusion Drive performance). As a result, for now if you would like to set up a custom spanned-volume in OS X, including using an SSD in a homemade Fusion Drive, you will have to use the following steps: Making the CoreStorage drive However, while Apple's Disk Utility can be used to repair problems with existing Fusion drives, adequately managing the CoreStorage volume currently requires the use of Terminal commands. This feature is the basis of Apple's new Fusion Drive technology its presence in OS X 10.7 and later allows you to create custom Fusion Drive setups and implement them on Mac systems that did not ship with a Fusion Drive configuration. This means that if you use an SSD as the primary drive, then as with Apple-configured Fusion Drives you will get fast data access when accessing frequently-used files. The CoreStorage volume-spanning feature not only increases a single volume's storage beyond the capacity of a single drive, it also prioritizes storage to the primary drive in its logical volume. It was introduced in OS X Lion for its full-disk encryption options with FileVault 2, but in addition allows for volume spanning, where multiple drives in the system can be combined into one logical volume for the OS to use. CoreStorage is Apple's volume manager that provides an interface between the OS and physical volumes on the drive.

How to partition a mac fusion drive