There’s plenty of examples of doing this already but it’s as simple as: $ diskUtil coreStorage create ssdDisk hddDisk $ diskUtil coreStorage createVolume VolumeUUID jhfs+ "fusion Drive" 100% Seems to be working so far, although with typical Apple there’s no documentation on how files/objects are moved between the SSD and HDD components

Create the following plist file somewhere useful, e.g. /Library/LaunchDaemons/com.local.noatime.plist <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"> <plist version="1.0"> dict> <key>Label</key> <string>com.my.noatime</string> <key>ProgramArguments</key> <array> <string>mount</string> <string>-vuwo</string> <string>noatime</string> <string>/</string> </array> <key>RunAtLoad</key> <true/> </dict> </plist> Then run the following to pick up the change, or indeed, reboot: % sudo launchctl load /Library/LaunchDaemons/com.local.noatime.plist And you should now see the root file system mounted with noatime option, which should improve longevity of SSD boot drives

$ umount /Volumes/UNTITLED $ sudo ./wbfs -p /dev/disk4s1 init $ sudo ./wbfs -p /dev/disk4s1 df wbfs tot:298.08G used:0.08G free:298.00G $ sudo ./wbfs -p /dev/disk4s1 ls wbfs empty Then just use WBFS for macos X to add in the backup images you’ve created previously.