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We’ve been waiting and waiting for Apple to release the next version of OS X Mountain Lion in hopes that the next full version would have all the necessary components to setup a Fusion drive on any Mac capable of installing a hard drive and SSD together. A little over a week ago, Apple released OS X version 10.8.3 and, with one small caveat, our hopes were fulfilled.<\/p>\n
But before we get to showing you exactly how to setup your own DIY Fusion drive, I’d like to dispel some mis-information that has been floating around the web. Up until now, most of the reports you’ve read about creating your own DIY Fusion drive on a machine have been incomplete. There have been many tutorials on how to create a Core Storage volume that have been labeled as “how to create a Fusion drive”. They are two similar, yet different drive configurations. I’ve addressed a lot of this information in comments on the OWC Blog, but figure it would be a good idea to review and further explain what a Fusion drive actually is as opposed to a Core Storage volume.<\/p>\n
When Apple introduced Lion, they added a logical volume manager (Core Storage) to the OS. The key factor to Core Storage is that it allows a single volume to span multiple physical disks. Which makes the Fusion drive possible, but it isn\u2019t the only aspect.<\/p>\n
What turns a Core Storage drive into a Fusion drive is the introduction of automated storage tiering to mix. This has actually been around since 2005 on larger scale networks where the software moves data across different disk types and RAID levels in order to balance space, cost and performance requirements of a server. Prior to the automation software, this type of data manipulation was done manually.<\/p>\n
Most of the terminal command setups we\u2019ve seen online are only initiating that Core Storage volume. It needs the software to run the automated storage tiering to make it a true Fusion Drive. Until now, we\u2019ve only seen that software component in the 2012 Mac mini and 2012 iMac models that ship with their specific builds of 10.8.2<\/p>\n
You don\u2019t find out that it\u2019s not truly \u2018Fusion\u2019 until the SSD portion has been completely filled up. And even then \u2013 what\u2019s on the SSD continues to be read at full SSD speed, so it\u2019s only the new data writes (where existing data on SSD is not being replaced) and subsequent reads of that HDD stored data that are slower due to being on the HDD. The way a Core Storage volume works, it really makes people think they\u2019ve created a true Fusion drive. So, now that you know the difference, the question on everyone’s mind is…<\/p>\n
Step 1 \u2013 Have a copy of your computer\u2019s data.<\/strong><\/p>\n This process will erase both the installed SSD and hard drive, so if you have data on one or both of these drives, you\u2019ll want to have a copy that\u2019s not on either of the two drives that are going to be part of the Fusion array. If you are installing both a new SSD and a new platter-based drive into, you can put your original drive in an external enclosure<\/a>, and your data will be there, out of the way. If you\u2019re using the same drive that you already have installed, you will need to copy that drive\u2019s contents<\/a> to an external one.<\/p>\n Step 2 \u2013 Download 10.8.3 from the App Store.<\/strong><\/p>\n And here’s the caveat I mentioned earlier: At this time, you absolutely need to download OS X 10.8.3 from the Mac App Store. To further clarify, we’re talking about the FULL VERSION – not the update. This is the only<\/strong> way to assure you have the correct version of Disk Utility on your recovery partition. You can do this by going to App Store > Purchases > Click the Download button to the right of OS X Mountain Lion. ***you may need to actually purchase ML if it does not show in the Purchases screen.<\/p>\n Step 3 \u2013 Move the Installer to your Desktop.<\/strong><\/p>\n The Mountain Lion install package will show up in the Applications folder once downloaded. Move it to your desktop.<\/p>\n Step 4 \u2013 Right click on the package icon and select Show Package Contents.<\/strong><\/p>\n Step 5 \u2013\u00a0 Navigate to Contents > Shared Support. <\/strong><\/p>\n There you will see InstallESD.dmg. Drag this image file to your desktop.<\/p>\n Step 6 \u2013\u00a0 Using Disk Utility, restore the InstallESD.dmg file to an External Hard Drive or USB Flash Drive at least 8GB in capacity.<\/strong><\/p>\n This should be a separate<\/em> drive other than your clone or Time Machine backup.<\/p>\n Step 7 \u2013 Install the new drive(s) in the computer you\u2019re upgrading.<\/strong><\/p>\n See our video page<\/a> for our step-by-step instructions on installing one or both drives into your machine.<\/p>\n Step 8 \u2013 Boot to the newly created 10.8.3 Installer.<\/strong><\/p>\n Boot the machine while holding down the Option key at startup and selecting the external hard drive or USB flash drive with the 10.8.3 installer (it\u2019ll have the orange icon).<\/p>\n If you installed at least one brand new drive, you will likely get a message about a disk being unreadable. That\u2019s okay; just click \u201cIgnore.\u201d\u00a0 We\u2019ll be initializing it over the next couple of steps.<\/p>\n You can then open Terminal. You can find it in Applications\/Utilities\/Terminal.app<\/p>\n Step 10 \u2013 Find Your Disk IDs.<\/strong><\/p>\n In Terminal, type: diskutil list<\/span><\/p>\n This will have the command-line version of Disk Utility (diskutil) that lists all the disks attached to your computer. In the results, you will find the disk IDs of the HDD and SSD. Take note of these ID numbers. In most cases (2 drives internally and booted from the external), the IDs will be \u201cdisk0\u201d and \u201cdisk1.\u201d However, individual results may vary, depending on your setup, so you\u2019ll want to make sure you have the right drives.<\/p>\n Step 11 \u2013 Create the Fusion drive array.<\/strong><\/p>\n In Terminal, type: diskutil cs create drivename driveIDs<\/span><\/p>\n This is the command that actually tells your Mac to tie the drives together in a Fusion array.<\/p>\n Broken down, the step does this:<\/p>\n Once you enter in this command, it\u2019ll do its thing and set-up the drives into an array for Fusion.<\/p>\n Step 12 \u2013 Get ID information for Fusion array.<\/strong><\/p>\n In Terminal, type: diskutil cs list<\/span><\/p>\n This will give you a listing showing any Core Storage Logical Volume Groups (aka Fusion drive). You will need to do two things here. First, copy the long alphanumeric string for the Logical Volume Group, then note the Free Space for it. You will need both of these for the next step.<\/p>\n Step 13 \u2013 Format the Fusion drive so you can put files on it.<\/strong><\/p>\n In Terminal, type: diskutil cs createVolume groupString jhfs+ volumeName size<\/span><\/p>\n This command creates a volume on the Fusion array where you can place your files. Again, since some important stuff is going on here, let\u2019s break down the command.<\/p>\n Once you have this information entered, hit Return and let it do its thing; the Fusion Drive will then be available in the Finder.<\/p>\n Step 14 \u2013 Close Terminal and <\/strong>Install OS X<\/strong>.<\/p>\n Now that we have created the CoreStorage volume named Fusion, we can now install the OS and bring over your data.<\/p>\n Close your Terminal window and select the option to Install OS X. Follow the prompts for installation, choosing your new Fusion drive as the destination. You will need an Internet connection to do this; an Ethernet connection is preferable, though you will also be able to use an AirPort connection, albeit at slower speeds.<\/p>\n Step 15 \u2013 Migrate over your information.<\/strong><\/p>\n As part of the setup for your new installation, you will be asked if you wish to import data from another disk; you will want to. Attach and select your clone or Time Machine backup and Migration Assistant will bring over your data.<\/p>\n Step 16 \u2013 Enjoy your new installation.<\/strong><\/p>\n Once migration has completed, shut down your computer and disconnect your clone. At this point, you will have OS X running on a Fusion drive on your computer. You can now use it like you would any other drive.<\/p>\n As with any drive setup, there are pros and cons to a Fusion array. The pros, as mentioned at the beginning of the article are that it appears single volume and works automatically to keep the best speed. However, there are a couple of cons that you should also be aware of.<\/p>\n You will need a backup.<\/strong><\/p>\n While a backup plan for your computer is something you should have anyway<\/a>, this becomes even more important for Fusion drive equipped Macs. The way Fusion is set up, if either the hard drive or the SSD fails, the data on both drives is lost. Having a reliable, frequent backup plan will be essential in protecting against data loss.<\/p>\n Performance may not be enough for high-end professional use.<\/strong><\/p>\n Apple claims near-SSD performance for Fusion-equipped drives. For casual use (email, Web browsing, basic iPhoto use, etc.), this is largely true. From testing both in-house and by Lloyd Chambers of Mac Performance Guide<\/a>, a Fusion drive will first fill the faster SSD portion, then start filling the slower hard drive. Once writing is complete, data will be moved from the SSD to the hard drive until there is 4GB free on the SSD again.<\/p>\n The trouble comes when you start working with larger files, such as with pro audio, video and large-scale photo work. Often, these files far surpass the 4GB size, so you will see fast SSD transfer speeds followed by a precipitous drop in speed when it transfers over to the hard drive. For a full rundown of testing, check out Lloyd\u2019s writeup at Mac Performance Guide<\/a>.<\/p>\n![\"\"](\"https:\/\/eshop.macsales.com\/blog\/wp-content\/uploads\/2012\/11\/terminal-icon.jpg\" "\\"\\""){kind=icon}
Step 9 \u2013 Open Terminal.<\/strong><\/p>\n![\"\"](\"https:\/\/eshop.macsales.com\/blog\/wp-content\/uploads\/2012\/11\/fusionSS-2.gif\" "\\"\\"")
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<\/p>\nThings to consider before committing to a Fusion setup<\/h2>\n