Make you rown Fusion Drive

Can’t justify a big SSD upgrade? This option costs as little as $37

Buying a 500GB or larger SSD can cost upwards of $100, but making your own Fusion Drive remains an option on a tight budget. We suggest using a StarTech USB enclosure ($15.53, amazon.com) and no smaller than a 120GB SSD ($21.99, crucial.com).

Follow the steps at bit.ly/macindsk, using an 8GB USB thumb drive that you’re happy to erase to create a macOS install disk. You may need this as a fallback to reinstall macOS, or restore a Time Machine backup of your complete system. Hold Alt at startup if you need to boot from it.

1. Prepare your Mac

Don’t proceed until you’ve got a complete backup of your Mac’s internal storage. Back up macOS and your files using Time Machine for ease at the end of this process. Connect your SSD and detach all other external drives to protect against accidental erasure. Then start up in macOS Recovery — see bit.ly/mfrcvry.

2. Get a list of disks

Choose Utilities > Terminal, type diskutil list, and press Return for a list of partitions on connected disks. Partitions are grouped by disk. Refer to the Size column to work out which disk is a match for the SSD you’ve connected. In our case, its identifier is disk2.

3. Identify targ et par titions

To avoid wiping the partitions that contain the Recovery system and (if you use it) Windows in Boot Camp, use the Name column to look up the partition where macOS is installed, and make a note of what’s listed under Identifier in that row. For us, disk0s2.

4. Group par titions

Type diskutil cs create Fusion, then a space, the identifier of your SSD, another space, then the identifier of the partition for your existing macOS installation. Press Return to create a logical volume group that identifies storage your Fusion Drive will use.

5. Gather more info

Type diskutil cs list and press Return for a summary of what was just created. Select the long code to the right of “+-- Logical Volume Group” and press Cmd+C. Note the free space number.

6. make usab le spac e

Type diskutil cs createVolume and a space. Press Cmd+V to paste the long code. Add a space, type jhfs+ “Macintosh FD” then a space. Divide the free space number by 1,000,000,000 and type the result to three decimal places, then g. Press Return. Wait for “Finished CoreStorage operation” and you can type again, then quit Terminal. Your Fusion Drive’s ready for a fresh copy of macOS or your Time Machine backup, using Recovery’s menu or a bootable USB installer.