2011 Mac Mini DIY fusion drive issues...help please

July 28, 2015 10:58 PM

The stock drive on my mid 2011 mac mini, model 5,2, recently became a brick. So, I got the idea I would create a fusion drive using a 120gb SSD and 1tb HDD. When I start the machine in (command+R) recovery mode, the SSD and HDD appear as separate drives. I had been expecting for disk utility to list the drives in RED with the option to "fix". How can I turn these two drives into a fusion drive? Is a Fusion drive even necessary? (~more info below~)

Hi all.
The stock drive on my mid 2011 mac mini (Model A1347 EMC 2442, aka model 5,2), recently became a brick. So, I got the idea I would create a fusion drive using a 120gb SSD and 1tb HDD. The first SSD that OWC sent me wasn't recognized in either internal bays or in an external enclosure, which was frustrating. Luckily, the kind folks at OWC agreed to send me a new SSD. While I waited for it to arrive I reinstalled a time machine backup of Yosemite (10.10.4) to the 1tb HDD just so I could have a working computer. Today I installed the replacement SSD drive and thankfully it is recognized and available in disk utility.
So, when I start the machine in (command+R) recovery mode (or from a bootable Yosemite usb stick) and launch disk utility the SSD and HDD are listed in black as separate drives. I had been expecting/hoping for the disk utility to list the two drives in RED, meaning the two separate drives are seen as a broken fusion drive which disk utility would then provide the option to 'fix'. This is according to all of the instructions I have read about creating a fusion drive and I am not savvy enough to know what else to do at this point. Fwiw, I believe both SSD and HDD are formatted Mac OS Extended (Journaled) and GUID partitioned.
-What am I missing/doing wrong?
-Do i need to erase all info from HDD before attempting "fusion creation"?
-How can I turn these two drives into a fusion drive?
-Is a Fusion drive even necessary? Should I instead just run two different drives? Plop bare bones Yosemite on the SSD and use migrate assistant to (re)load my digital detritus to the HDD?
My goal is simply to have a fast stable machine that is as idiot proof as possible. If I had the money I would buy one large SSD, but I don't, even this was a unfortunate wallet stretching.
~Thank you for your help, please let me know if more info is required~
cheers!

posted by 5lbauthority to Computers & Internet (5 answers total)

If stable and idiotproof are high priorities, I'd just keep your OS, apps, and high priority stuff on the SSD and your photos and music on the hard disk. My experience is that when you transgress Apple's vision for your connected life, it'll bite you certainly some day.

I forget the exact jiggery-pokery to do this, but:
- avoid migration assistant if you can help it. My impression is that the wise folk of MacOS don't use it, or regret it when they do.
- it wouldn't hurt if both drives were blank, but I won't promise that it will help.
- I think you'll want a couple of command line incantations of diskutil.
- You may need to reboot back into Recovery after the command line stuff is done - the OS isn't super great at coping when you're attempting extra-official mischief like this.
- and I haven't done this since Fusion was a new feature, whenever that was, so a pinch of salt is owed to my advice.
posted by wotsac at 11:38 PM on July 28, 2015

I looked into doing this a year or two ago with a 2011 iMac and came to the conclusion it was too hard. There's a lot of web pages about hacking up your own Fusion drive most dating to 2012 when Apple introduced the technology. After reading a bunch of them I decided it wasn't worth the risk and trouble. In particular, people were having problems with systems that were working and then stopped working after upgrade. Not saying it's not possible, but it's not as easy as we'd like.

If you do try to create a fusion drive, I believe you effectively have to erase both drives entirely.

On my 2011 iMac I just have two separate drives. OS and most stuff on the SSD, big video files and music and stuff on the HDD. If you're comfortable using the command line you can create symlinks for folders like ~/Videos and pretty much everything will Just Work. Pay extra attention that Time Machine is backing up both drives though.
posted by Nelson at 8:22 AM on July 29, 2015

Now that I'm on a computer, in the morning, and sober, I can google up some instructions ('DIY Fusion drive'). First, I'll repeat that if you really want to make sure that your computer is stable and idiotproof, don't do this. Apple doesn't go out of its way to ruin your day when you don't use their tools, but sooner or later, they probably will.

- you do need to back up the hard drive - the data part of the disk will be erased.
- There may be ways to avoid doing command-line diskutil commands, but it doesn't seem like Apple makes doing this easy.
- This article seems like a fairly straightforward guide to setting up a Fusion drive and preserving your recovery partition. It's what I'd do if I was going to set up a Fusion drive in my 2011 Mini.
posted by wotsac at 8:29 AM on July 29, 2015

The article wotsac just linked looks very promising, and a lot less squirrely than the stuff that scared me off when I looked into this.
posted by Nelson at 8:58 AM on July 29, 2015

I ran a DIY Fusion drive on a 2012 Mini until very recently (I went all-SSD when prices started dropping again). I had no problems whatsoever, including doing Mountain Lion -> Mavericks -> Yosemite upgrades.
posted by zsazsa at 9:40 AM on July 29, 2015