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.
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Apple's New Fusion Drive Works on Older Macs
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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.
I've been using a Seagate Momentus 500GB Hybrid drive for 2 years in my 2008 MBP after I ran out of space on the original 200GB drive. I was curious myself about how a hybrid drive would perform vs this new Fusion drive and found this article:
http://www.zdnet.com/mac-fusion-drive-pro-users-beware-7000006661/
That's what I was going to say. Misleading article title is misleading. It's the software that works on other Macs, not the drive itself.
You're wrong. The Fusion tech that Apple is using isn't just a RAID. It's about the system automatically moving files to the place where it is more efficient based on usage.
For example. Lets say that you are a photo nut. You are in and out of your iPhone and Aperture libraries at least once every day, sometimes 3 or 4 times. So the system sees this and puts that stuff (the libraries, your plug ins etc) on the SSD. But Garageband that you go into maybe once every 3 months, well it puts the data file, loops etc for that on the hard drive.
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So what? It doesn't change that the headline was totally false.
YES!!!!! This was the first thing I thought after the announcement of Fusion Drive. OWC offers an SSD and adapter to fit into older iMacs in place of the Superdrive. My thought was: can I set this up as Fusion?
I contacted Apple about and the rep did not seem to think it was possible. I figured the problem might have to do with the 4GB "write cache", but apparently it is possible.
Now I wonder two things:
1) If any two drives work, then why note a Fusion setup with 256GB of SSD instead of 128GB?
2) Should I invest more money in beefing our two 2009 iMacs or simply look to upgrade them next year to something newer?
I contacted Apple about and the rep did not seem to think it was possible. I figured the problem might have to do with the 4GB "write cache", but apparently it is possible.
Now I wonder two things:
1) If any two drives work, then why note a Fusion setup with 256GB of SSD instead of 128GB?
2) Should I invest more money in beefing our two 2009 iMacs or simply look to upgrade them next year to something newer?
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...
According to his next two posts, its looks as if it is operating at the block level.
In other words, the magic sauce is ready to pounce. You just got to put the pasta onto the plate, and the magic sauce will flow.
Did you not read the article? When he stopped reading the data the OS starting shuffling the data around and keeping the stuff he was reading (folders 7-10) on the SSD and moving everything else to the HDD.
You're missing the point. It's not the drives that are working the file management magic, it's the OS itself. His article essentially confirmed that. All he did was build a logical grouping in diskutil. The OS handled the rest, and quite seamlessly so. That's pretty cool.
Lots of confusion
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.
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.
Nice - was thinking of getting a 2012 iMac but might get the refurb 2011 instead and install my own SSD.
You can find a 256GB these days for roughly $160ish.
You can find a 256GB these days for roughly $160ish.
Is it the "same"? Of course it is. He used Apple's Disk Utility and a stock Mac OS X system. Apparently Fusion is already built into all Macs, you just need to install an SSD and enable the Fusion volume.
It sounds like it. John Siracusa on the latest "Hypercritical" podcast spoke at length about how Fusion leverages CoreStorage and that this may very well have been a feature Apple wanted to announce at WWDC and ship with Mountain Lion at launch.
Because it is based on CoreStorage, it should be able to be run from the Terminal as Mr. Stein has done. However, it may very well be unstable and therefore why Apple is officially saying it cannot be done and is not supported via the GUI.
Perhaps I misunderstood your comment, you seemed to be implying that it was the drive doing the work. Sorry if I read your comment wrong.
It is a matter of semantics. I'd say it is "RAID-like" in that several drives are joined using software into one logical volume.
The difference is that is a "normal" RAID system one typically uses identical drives. Here we uses one HDD and one SDD and the "magic" is that when you do this Mac OS X will place the files you access the most on the faster drive.
QUESTION: How good is this new software? Will it work if it sees two HDDs and one SSD made into a logical volume? What if you have multiple SSDs?
I've done systems level software development for years (decades really but not on Mac OS X) and some times I'l com up with a fully generalized solution because it is just as easy as the special case. So with luck Fusion will do something like this: Look at all the drives in the logical volume and sort them by speed. Place most used files on fastest drive untill it is (say) 75% full then place files on next fastest drive ntill mostly full and so on. I have no idea if the developer did this or if he only handled the special case of one HDD and one SSD.
Is this a Fusion Drive or just caching?
The following line in the MacRumors description makes me question whether this is a true Fusion setup or just a form of hybrid caching:
Here is a relevant quote from the Apple iMac Fusion Drive marketing material:
It is my understanding that in the Fusion drive, the most frequently used information will stay on the SSD. It seems that part of the Fusion technology is on the fly "disk" optimization that will restructure the drive so that the most frequently used blocks are in the faster (SSD for Fusion) section of the drive. The IMPLICATION in the Apple marketing material is that this change in disk layout is a long term process that will improve over days/weeks of usage.
So far I have found a lot of speculation about Apple Fusion Drives but very little that truly documents how the technology works.
The following line in the MacRumors description makes me question whether this is a true Fusion setup or just a form of hybrid caching:
Here is a relevant quote from the Apple iMac Fusion Drive marketing material:
It is my understanding that in the Fusion drive, the most frequently used information will stay on the SSD. It seems that part of the Fusion technology is on the fly "disk" optimization that will restructure the drive so that the most frequently used blocks are in the faster (SSD for Fusion) section of the drive. The IMPLICATION in the Apple marketing material is that this change in disk layout is a long term process that will improve over days/weeks of usage.
So far I have found a lot of speculation about Apple Fusion Drives but very little that truly documents how the technology works.
Perhaps I misunderstood your comment, you seemed to be implying that it was the drive doing the work. Sorry if I read your comment wrong.
Completely wrong.