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Apple's New Fusion Drive Works on Older Macs

One of the interesting additions to Apple's iMac and Mac mini lines announced last week is Fusion Drive, a hybrid storage system that combines a 128 GB solid-state drive (SSD) with a 1 TB or 3 TB traditional hard drive into a single volume to offer the best of both worlds in terms of performance and storage space. Apple's software automatically manages the combined volume, placing the core system and other frequently used applications and files on the solid-state drive for faster access while keeping lower-priority applications and data on the traditional hard drive.

Mac developer Patrick Stein has been toying with his own Mac Pro setup and has managed to build his own Fusion Drive using command line tools. Stein configured an internal solid-state drive and a USB-attached traditional hard drive on his system and was able to combine them into a single logical volume as used for Fusion Drive.
Attached are a 120GB SSD (disk1) and a 750GB HDD (disk7) to my Mac. I attached the SSD via SATA to be sure that the system could figure out that it’s a SSD via SMART. The HDD is attached via USB. USB I chose to clearly see a difference in speed.
Stein then proceeded to test the setup, writing data first to the SSD and then to the traditional hard drive once the SSD had filled up. By preferentially accessing data that had initially been written to the traditional hard drive, Stein was able to watch as the data was automatically transferred to the SSD for faster access. Upon stopping the process, the system automatically pushed the data back to the traditional hard drive, and in one final step Stein began accessing the data once more and after about an hour was able to see it pulled back onto the SSD.

In several follow-up Tumblr posts, Stein details further explorations into how Fusion Drive works, noting that he was able to use not only the default HFS+ file system for OS X with it, but also ZFS. All of Stein's work was performed with a standard installation of OS X 10.8.2.

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28 months ago

So he has an internal SSD and an external HDD with a single drive letter, what makes that a "fusion" drive? Nothing! There's no proof this is what Apple calls Fusion Drive technology. The article is a fail.

P.S. There's Windows software out there that will combine various drives into a single "hybrid" volume. Does that mean that's "fusion" drive software? I think not.


Respectfully disagree. The article explains that the file swapping is working in "fusion" mode, which is really what makes it a fusion drive in the first place.

Regardless, my guess is Apple blocks this option in an update.
Rating: 20 Votes
28 months ago
There seems to be a lot of confusion about what a Fusion drive is... The Fusion drive is software based, it is not hardware. A hybrid drive IS hardware, and is NOT what Apple's marketing department has called a Fusion Drive. The Fusion drive is a SSD & a HDD in an iMac, and at the OS level, it is picking and choosing where to store programs / data. So the title of this article is correct, if you also own a Mac, and own a SSD & HDD attached to that Mac, you can also have a "Fusion" drive (assuming Apple doesn't shut down these command line hacks). This isn't misleading at all. Will it perform the same as the Mac version? That depends on what SSD / HDD Apple is using versus what SSD / HDD YOU are using.

I have a Mid 2011 Mac Mini, with a SSD / HDD installed, and I cannot wait to try this out, I currently have my home directory on the HDD to save room, but with this setup, the OS can choose where to put everything, which is truly ideal.
Rating: 19 Votes
28 months ago
So he has an internal SSD and an external HDD with a single drive letter, what makes that a "fusion" drive? Nothing! There's no proof this is what Apple calls Fusion Drive technology. The article is a fail.

P.S. There's Windows software out there that will combine various drives into a single "hybrid" volume. Does that mean that's "fusion" drive software? I think not.
Rating: 13 Votes
28 months ago


Mac developer Patrick Stein (https://twitter.com/jollyjinx) has been toying with his own Mac Pro setup (http://jollyjinx.tumblr.com/post/34638496292/fusion-drive-on-older-macs-yes-since-apple-has) and has managed to build his own Fusion Drive using command line tools.


So the headline is false. It's not Apple's Fusion Drive at all.

It should read more like "Computer Geek manages to emulate Apple's Fusion Drive in his own setup"
Rating: 11 Votes
28 months ago
Is this really exactly the same as Apple's implementation of Fusion Drive? That wasn't made clear to me by the article.
Rating: 10 Votes
28 months ago

Isn't this called a seagate XT and has been out for over a year??


this thread is one infinite loop.
Rating: 9 Votes
28 months ago

Correct me if I am wrong, but isnt the Fusion drive just some RAID'ed drive?


It isn't a RAID configuration at all. The drives are "joined," but the real "magic" is how files are swapped back-and forth based on use.
Rating: 7 Votes
28 months ago

So he has an internal SSD and an external HDD with a single drive letter, what makes that a "fusion" drive?


Did you RTFA? His results would indicate that there's a software layer doing some additional work here besides just managing a typical volume group. What's more, the behavior is clearly more complex than a simple caching system using the SSD. The magic behind Fusion looks to be at the OS layer itself, because he pretty much had to do no major configuration other than creating the volume grouping. His test would suggest that it would be quite easy to roll your own file-level tiering setup using just the functionality built into the OS.

His test may have been relatively simple, but it certainly showed something interesting. I would postulate that it probably rolled out with 10.8.1 or 10.8.2. The larger question is if it operates at file-level or at the block level...
Rating: 7 Votes
28 months ago

Isn't this called a seagate XT and has been out for over a year??


Oye. No reading of the article or any comments, eh?

Read up here:

http://www.anandtech.com/show/6406/understanding-apples-fusion-drive (http://www.anandtech.com/show/6406/understanding-apples-fusion-drive)
Rating: 6 Votes
28 months ago

So he has an internal SSD and an external HDD with a single drive letter,


OSX has no concept of "drive letter." WTF are you talking about.


what makes that a "fusion" drive? Nothing! There's no proof this is what Apple calls Fusion Drive technology. The article is a fail.


The article demonstrates automatic tiered storage, which is exactly what the Fusion drive is.


P.S. There's Windows software out there that will combine various drives into a single "hybrid" volume. Does that mean that's "fusion" drive software? I think not.


AFAIK, Windows has support for combining drives as a JBOD volume (literally means "just a big old disk"). That is not the same thing as automated tiered storage, in which the operating system manages which data gets written to which volume based on usage requirements.
Rating: 5 Votes

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