Feeling the need for speed? Back in 2012, Apple introduced the Fusion Drive to Macs in the Mac mini and iMac, merging the speed of a Solid State Drive (SSD) with the low cost of high capacity hard disk drives (HDD). The result is that users get fast boot up and app loading, while having access to tons of storage. In this article, the Rocket Yard shows you how to create your own Fusion Drive for an older Mac to give it a major boost.
What You’ll Need:
- A Mac mini, iMac, Mac Pro or “Hackintosh” with at least two available SATA data/power ports
- OS X 10.8.2 or later
- Solid State Drive: MacSales.com offers a wide lineup of SSDs that are perfect for a Fusion Drive
- Hard Disk Drive: Take a look at the MacSales.com selection of 2.5-inch and 3.5-inch HDDs
- Familiarity with the OS X Terminal command line
Installation of Drives
Once again, remember that you’ll need a Mac with enough internal space and at least two SATA connectors in order to put both an SSD and HDD inside. Fortunately, OWC has a library of videos showing how to open and install drives. Note that the proper tools — a spudger, guitar pick, and suction cups are necessities for an iMac teardown — and some skills are required in order to take the old drive out and install a new one.
OWC’s Data Doubler mounting solutions are highly recommended for installing both the HDD and SSD that you’ll be placing into your Mac. Data Doublers are available for Mac minis and iMacs that replace the built-in optical drive (AKA SuperDrive) with a second drive, while older (pre-2013) Mac Pro models have four SATA hard drive bays with internal hard drive carriers. Adding a 2.5-inch drive to a 3.5-inch drive bay in a Mac Pro is easy using OWC’s MultiMount (photo right), and that same product can be used to put up to two 3.5-inch drives in a 5.25-inch optical drive bay.
Needless to say, installation of extra drives is much easier in Mac Pro and Hackintosh devices, since they already have multiple drive bays that are easily accessible. The Mac mini and older MacBooks are next in terms of ease of upgrading, while iMacs can be difficult to upgrade.
There’s also one other solution — using an external OWC ThunderBay 4 or ThunderBay 4 mini (see image below) with an SSD in one bay and a large HDD in another bay as a Fusion Drive. This is very useful for storing large iTunes libraries with many video files, as it places recent movies and TV shows on the SSD for quick retrieval and improves access time for less frequently watched videos as well.
Boot into OS X
Next, you’ll want to install OS X and boot the device into the operating system. For those who are planning on making the Fusion Drive the boot drive, you’ll want to boot the Mac from a bootable USB Install Drive with the latest compatible version of OS X. Fortunately, The Rocket Yard has articles on how to create USB Install Drives with DiskMaker X to help you with that task.
Now comes the fun part, working with Terminal!
1) Launch the Terminal app. It’s located in Applications > Utilities > Terminal. You can also launch it in seconds by pressing Command-Space on the keyboard, then typing in terminal and pressing the Return key.
2) We want to see a list of the drives installed in the Mac. Type in the following command at the terminal prompt:
A sample of what the output of the diskutil command produces can be viewed here:
3) For each drive, there will be a mount point listed in the format:
The # is a number assigned to the drive by OS X. Find the mount points for the SSD and HDD that will make up the Fusion Drive, and write them down.
4) Next, let’s type in a command to create the logical volume group using OS X’s Core Storage. This acts like a container for the pooled drives. We’ll need the exact drive mount points we found in the last step – aren’t you glad I had you write them down? The command has the following format:
diskutil coreStorage create LOGICAL_VOL_GROUP_NAME DRIVE_1 DRIVE_2
LOGICAL_VOL_GROUP_NAME is a name that defines your storage group, while DRIVE_1 is the mount point for the SSD and DRIVE_2 is the mount point for the HDD. As an example, let’s assume that we call the group name “FUSION”, that the mount point for the SSD is /dev/disk1 and the mount point for the HDD is /dev/disk2. In that case, we’ll execute the following command in Terminal:
diskutil coreStorage create FUSION /dev/disk1 /dev/disk2
5) We’re almost there. The last command creates the logical volume where data is stored when we’re done. This command requires that we find the LVG UUID – that’s a unique identifier assigned by OS X to all storage groups. That ID is created by the command in step 4 and is displayed at “Core Storage LVG UUID”. Write down the ID.
Our final command has the format:
diskutil coreStorage createVolume lvgUUID type name size
You have the LVG UUID from the last step, and that goes into the lvgUUID spot. “type” refers to the file system that will be used, which should be the OS X native file system Journaled HFS+ . That is abbreviated for terminal as “jhfs+”. For “name” enter a name for the volume. OS X usually calls this “Macintosh HD”. The “size” is the volume size, which can be entered as numbers in GB, TB, or as a percentage. Since we want to use the entire storage pool as our Fusion Drive, we’ll enter 100%. Here’s the final command to enter (be sure to replace the lvgUUID with the one you wrote down):
diskutil coreStorage createVolume 89E965C6-2AF7-4AFA-ABDC-DC49ECA31E32 jhfs+ “Macintosh HD” 100%
6) After the command has executed, you’ll have a Fusion Drive and the volume should be viewable from within Disk Utility from your USB boot drive. Go ahead and install OS X on the Fusion Drive, selecting it as your installation drive.
Disabling a Fusion Drive
If you should ever need to replace a bad drive in your Fusion Drive or want to upgrade either the SSD or HDD drive — or both — you’ll need to disable the Fusion Drive. This simple Terminal command does the job:
diskutil coreStorage delete lvgUUID
To find the lvgUUID, just run the diskutil list command again from Terminal. Replace lvgUUID with the real identifier, and execute the command — it breaks the fused drive. Remember that all data on those combined drives is lost, so back it up first!