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Create a Fusion Drive with a Recovery Partition Storage Devices
There are many step-by-step guides on the internet that explain how to add an SSD to an existing Mac, and create a 'Fusion Drive' that has the speed of an SSD, but also the capacity of a Hard Drive. All these guides fall short in one way that was important to me.

Creating the Fusion Drive the way these walkthroughs say (including OWC's exceptional guides), destroys the Recovery Partition that exists on the drive. Without a Recovery Partition, you cannot enable FileVault2, and will need some other external boot drive if you ever need to perform maintenance on your internal drives. For a laptop computer that might be far from home, not having a Recovery Partition was unacceptable to me. Also note that if you buy a Mac from Apple today with Fusion Drive, it DOES come with a Recovery Partition, so it is indeed possible to do.

It turns out that Apple's Core Storage technology is more flexible than these walkthroughs give on. You can enroll an individual partition of a drive in a Fusion Drive, instead of the whole drive. This means that you can join just a specific data partition of your HD with an SSD, and leave the Recovery Partition intact.

I've created a Fusion Drive (SSD + Original HD), that HAS a Recovery Partition, and is now encrypted with FileVault2. It is a lot faster than the original, so I'm calling it a success.

Steps to reproduce:
  • Make a bootable clone to an external disk (using SuperDuper or CCC).
  • Boot off the clone drive, make sure it's good. (Hold down the Option key when booting for a menu of available boot disks)
  • Shutdown. Install the SSD per OWCs excellent install videos. I used OWC's 'Data Doubler kit,' and am quite happy with it.
  • Boot off the clone again.
  • Run Terminal.app.
  • Determine your disk ID's by typing diskutil list at the prompt.
  • The SSD will likely be disk0. The original HD will likely be disk1. Partitions on the HD will likely appear as follows below.
  •   disk1 GUID_Partition_Scheme
      disk1s1 EFI
      disk1s2 Apple_HFS - This is your actual data partition (typically 'Macintosh HD')
      disk1s3 Apple_Boot - This is your Recovery Partition
      
  • Note: The trick is to enroll just the data partition of your HD into the Fusion Drive, and not the whole disk. Next step does that by enrolling 'disk1s2' (the data partition), instead of the whole disk ('disk1'). All the walkthroughs say to enroll the whole disk ('disk1'), and that is the major way we are diverging here.
  • Issue the following Terminal command:
      sudo diskutil cs create [ArbitraryName] disk0 disk1s2
      
    Note: [ArbitraryName] should have spaces and special characters escaped. I used 'Fusion,' to avoid any special characters, so I couldn't mess up.
  • Caution: The step above will wipe all data from your data partition disk1s2. That's an unavoidable step in the process, and is why we made a bootable clone first.
  • The final output of the previous step returns a UUID (ex., 352D9D2B-E0F2-4A16-B583-A257802EC74C) for your new CoreStorage volume. Copy that to your clipboard.
  • Issue the following Terminal command:
    sudo diskutil cs createVolume [paste the UUID here] jhfs+ [ArbitraryDriveName] 100%
     
    Note: [ArbitraryDriveName] should have spaces and special characters escaped. I used Macintosh\ HD. You can always use something simpler, and rename the drive later in the Finder.
  • Copy the contents of the external clone back to the Mac (using SuperDuper or CCC) again.
  • Reboot, from the internal hard drive (fusion drive, yeah!). Disconnect the external drive. Don't erase the external yet, in case something went wrong.
  • Test that your Recovery Partition still works (it should), by rebooting with Command+R held down. Do the recovery tools load? If so, then it is a success!
  • Reboot to normal internal HD. Does everything look fine? If so, then now you can activate FileVault2.
  • Assuming no problems have occured, NOW you can erase your external temporary clone.
If you accidentally damage the Recovery Partition on your HD, you can re-create it by running the MacOSX installer from the clone. Once re-install is done on your HD, you can re-start the directions above at the fourth step, and try again.

The hint is pulled from the MacOSXHints forums site, here. The step-by-step instructions are contained in post number eight of that thread.

[crarko adds: I don't have the hardware to try this out. If I did do this, I would probably keep the cloned boot drive around a few days, just for paranoia's sake.]
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Create a Fusion Drive with a Recovery Partition
Authored by: paulw on Apr 23, '14 07:26:59AM

When you boot holding down the option key, do you see the recovery partition?

I believe that what you described is essentially what I did, too (following a guide). I have a working recovery partition bootable by holding command-R, but it doesn't show up in the boot drive selections when holding the option key.



[ Reply to This | # ]
Create a Fusion Drive with a Recovery Partition
Authored by: ila225 on Apr 23, '14 10:19:05AM

It also depends on which version of the OS you're using to make the fusion drive AND the age of the Mac you're running.

I don't know exactly if it is only in Mavericks of if Mountain Lion already supported this in the latest updates, but after creating a Fusion Drive the second hard drive actually contains a recovery partition.

For example, this is my FD:

$ diskutil list
/dev/disk0
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *256.1 GB   disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:          Apple_CoreStorage                         197.9 GB   disk0s2
   3:                 Apple_Boot Boot OS X               134.2 MB   disk0s3
/dev/disk1
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *1.0 TB     disk1
   1:                        EFI EFI                     209.7 MB   disk1s1
   2:          Apple_CoreStorage                         892.0 GB   disk1s2
   3:                 Apple_Boot Boot OS X               650.0 MB   disk1s3
/dev/disk2
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                  Apple_HFS Mac OS X               *1.1 TB     disk2

*don't mind the disk size as there are windows partitions I removed from the listing

But what you want to pay attention to is the size of both "Boot OS X" partitions. On the first disk, it is 134 Mb, on the second, it is 650 Mb.

Digging inside the second partition one will find the BaseSystem.dmg hidden from Finder, but visible through Terminal's ls command:

$ diskutil mount disk1s3
Volume Boot OS X on disk1s3 mounted
$ ls -lha /Volumes/Boot\ OS\ X/com.apple.recovery.boot/
total 972776
drwxr-xr-x  11 root  wheel   374B Jan 29 18:07 .
drwxr-xr-x  12 root  wheel   476B Apr 22 22:01 ..
-rw-r--r--@  1 root  wheel   809B Jan 29 18:07 .disk_label
-rw-r--r--@  1 root  wheel   3.2K Jan 29 18:07 .disk_label_2x
-rw-r--r--@  1 root  wheel   1.9K Oct 16  2013 BaseSystem.chunklist
-rw-r--r--@  1 root  wheel   459M Oct 16  2013 BaseSystem.dmg
-rw-r--r--   1 root  wheel   4.2K Aug 24  2013 PlatformSupport.plist
-r--r--r--   1 root  wheel   475B Oct 16  2013 SystemVersion.plist
-rw-r--r--   1 root  wheel   494K Jan 29 18:07 boot.efi
-rw-r--r--   1 root  wheel   361B Jan 29 18:07 com.apple.Boot.plist
-rw-r--r--   1 root  wheel    16M Oct 16  2013 kernelcache

Trying this on an iMac 27" late 2009, the Recovery Partition does NOT show up when holding the Option key. It is good to mention that the iMac late 2009 was built BEFORE Fusion Drives, thus leading me to conclude that part of its BIOS / UEFI system simply doesn't know to look for that particular recovery partition aside the standard one mentioned on the article.

It DOES show up on newer macs that were built AFTER Fusion Drive was available.

I hope this helps a bit. =)

Edited on Apr 23, '14 10:19:36AM by ila225


[ Reply to This | # ]
Create a Fusion Drive with a Recovery Partition
Authored by: cpragman on Apr 25, '14 06:05:37PM

@ila225 -
You didn't mention what OS you had this issue with. Fusion drives are allegedly supported on 10.8.3 and higher.
If you have 10.8.3 or greater, you can try booting from your temporary clone, and running the OSX Installer. Install a fresh copy of OSX on the original Internal HD. This should create a working OS on "Macintosh HD", and will also create the "Recovery HD" and "Boot_EFI" partitions. After doing that, create the fusion drive using the diskutil core storage commands (join the "Macintosh HD" partition and the SSD together, leaving the Boot_EFI and Recovery Partition undisturbed.

I've actually had to do this a few times myself.



[ Reply to This | # ]
Create a Recovery Partition after fusing?
Authored by: earthsaver on Apr 27, '14 10:00:40PM

I thought I used a tutorial that installed a recovery partition, but it turns out that wasn't the case. Rather than cloning and recreating my fusion drive from scratch, is there a workaround to add a recovery partition to my existing setup?

---
- Ben Rosenthal
MacBook Pro 2.8GHz - Mountain Lion
iPad 3 4G



[ Reply to This | # ]
Create a Fusion Drive with a Recovery Partition
Authored by: cpragman on May 03, '14 08:30:19AM

Running the installer again will create (or recreate) a missing recovery drive.



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Copy a Recovery Partition
Authored by: prwiding on May 12, '14 09:12:19AM
Carbon Copy Cloner (bombich.com) -- which has a free trial period -- provides a Disk Center which will copy a recovery Partition and create it on a disk that doesn't have one. If you do an Install Mavericks on an external drive, you can use that drive to re-create the recovery partition on an internal drive. Without cloning or affecting any other partitions.

This hint is quite true. In addition, you can install Mavericks on the SSD before creating the Fusion drive, and it will install a Recovery partition on the SSD. Then just refer to the partition that isn't the recovery partition when you create the Fusion drive.

I have installed a 240 GB SSD, and created 2 partitions: FusionToBe (179 GB) and AltBoot (60 GB). If you run diskutil list from a Terminal window, it will show you the device names. For this example, /dev/disk0s2 and /dev/disk0s3. You can then refer to /dev/disk0s2 when creating the Fusion drive, and /dev/disk0s3 will still be useable as a separate boot drive, if you hold the Option key down during startup. This still provides a larger SSD volume than Apple provided Fusion drives.

Edited on May 12, '14 09:26:05AM by prwiding


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