OS X Mountain Lion Could Support Fusion Drive on Legacy Macs

Image Credit: Fusion Drive on Mac Mini | Official Website

Last Wednesday, a developer revealed that the OS X Mountain Lion can support Fusion Drive and that it is also compatible with a makeshift hybrid storage device. This only proves that the technology can be used with legacy Macs that doesn’t come with the said hardware pre-installed.

Fusion Drive’s Compatibility with Hybrid Storage Device

When the company announced the Fusion Drive hybrid storage together with the redesigned iMac, Apple noted that their latest operating system could power it up without the need to update. This made some to wonder whether existing hybrid drives could work with current Macs.

In a Tumblr post created by developer Patrick Stein, he unofficially confirmed that the Mountain Lion can provide Fusion Drive support for current Macs. That’s because he was able to “build” a hybrid drive that’s compatible with Apple’s latest storage technology.

The developer set up a solid state drive and a separate hard drive using a Terminal version of disk utility. Stein used a SATA-connected 128 GB SSD and USB-attached 750 GB HDD in his working solution. He also used a Core Storage, the OS X feature that links two separate storage units into one volume group, to build a single logical volume.

To facilitate the file creation and transfer, Stein created a 466 GB HFS+ volume also known as Mac OS Extended. In order to test if it’s working as a Fusion Drive, he created a number of directories that are tantamount to 140 GB, and the data were funneled to the SSD until the 120 GB mark. The rest was written on the HDD directories.

Using the “dd” command, Stein prompted the device to force read the data at HDD and see whether any files were transferred to SSD. This is an activity that the Fusion Drive uses to determine which files are heavily accessed and should be relocated to the faster storage device.

The system started dumping data from SSD to HDD, and then the developer began to read out data from the HDD directories. After hours of force reads, the files can now be accessed from the SSD. This only means that the data transfer was successful.

Despite the success of Stein’s experiment, the process of configuring the hybrid storage devices is definitely not plug-and-play. Although the Fusion Drive is active and can be used on legacy Macs, it is unlikely for Apple to offer compatible hardware as an upgrade.

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