43

After gaining some experience with CoreStorage volumes, I reworked my first answer to generalize and facilitate it by adding some scenarios and deleting some dispensable steps. Basically there is one undocumented command to resize or expand a CoreStorage volume group and an inherent logical volume: diskutil cs resizeStack LVUUID size The command ...


42

Yes, you can create a fusion drive on older Macs, described in full length here: You obviously need both an SSD and a HD. Let's assume they are known to the OS as disk1 and disk7. You can check disk id by diskutil list. diskutil cs create bla disk1 disk7 to create it, where bla is the name you give to the fusion drive. diskutil cs list and take note of the ...


20

Looks like your MacSSD2 partition has been turned into a Core Storage volume. Core Storage is Apple's underlying system for disk encryption - I assume you enabled encryption when you created the partition? You can show the Core Storage volume group using the command diskutil cs list and then delete it using diskutil cs delete <volumegroup-uuid>, where ...


17

If you have Yosemite installed, diskutil now includes the option to rename a Core Storage logical volume group (LVG) from the command line: $ diskutil cs rename Usage: diskutil coreStorage rename lvgUUID|lvgName newName Rename a CoreStorage logical volume group. Do not confuse this with LV names. Ownership of the affected disks is required. So use ...


14

Yes and no. The Fusion Drive is taking advantage of Core Storage to act as one logical volume, which you see as a single volume but can actually be made up of multiple physical volumes (in this case, an SSD and an HDD). You can create and manage Core Storage volumes with the diskutil command in Terminal. (Disk Utility does not yet have extensive Core ...


13

I highly recommend completely backing up the machine before attempting this, either using TM with no exclusions set, or better yet, cloning the whole drive using a program like Carbon Copy Cloner. Unmount the Logical Volume: sudo diskutil unmount force /dev/disk1 Remove the Logical Volume Group and all of its contents: sudo diskutil cs deleteLVG B6308EC8-...


12

The following diskutil cs resizeStack command is vastly undocumented and as such potentially destructive. There might be an easy way outlined first and a long winding, time consuming hard way. Please backup your Mac OS X before proceeding. The not-as-long-as-expected way: A 2nd computer or an iPhone with the stackexchange credentials to enter the site ...


11

I am astonished about complexity of this problem (see @klanomath answer) and easiness to create it. That's why I tried to play with it and found a work around. My problem was the following: I had 500GB-disk. I created 150GB-Macintosh-HD partition on this disk using Disk Utility, leaving 350GB as a "free space". When I tried to format the free space into ...


11

You can't move the start block of a CoreStorage Volume Group ("BOOTCAMP" in your case) non-destructively (OK, there is a workaround: please check the Scattered Physical Volumes method at the end of my answer). The same is valid for non-CoreStorage partitions with on-board tools. AFAIK only iPartition and gparted work for the latter. Therefore you can't ...


10

I just finished creating a DIY Fusion Drive in my early 2009 MacBook Pro. It works great, and I figured out how to keep my recovery and Boot Camp partitions at the same time. I started with backups: Both a Time Machine and a Carbon Copy Cloner backup of my Mountain Lion partition, and a WinClone backup of my Boot Camp partition. All backups were saved to an ...


9

A bootable OS X partition (except the Recovery HD) either has the GUID 48465300-0000-11AA-AA11-00306543ECAC for a standard OS X partition, the GUID 53746F72-6167-11AA-AA11-00306543ECAC for a CoreStorage partition or the GUID 7C3457EF-0000-11AA-AA11-00306543ECAC for an APFS volume. The FFFFFFFF-FFFF-FFFF-FFFF-FFFFFFFFFFFF is an unknown partition type (but not ...


8

In addition to @jtbandes being right, you can create and manage logical volumes using CoreStorage, but according to the KB Article HT5446 there are some "limitations" to the Fusion drive. An alternative to the Fusion drive (which is basically a SSD AND an HDD grouped as a logical volume) is move the "/Users" folder to a HDD and leave all the OS X files and ...


7

The Fusion drive is an amalgam of the SSD and HDD. If either piece gets removed or fails, you lose all the data. It might be possible to retrieve some of it, but it would be a job for drive recovery experts. If you have a Fusion drive, it is possible to split it into the two separate pieces, resulting in a standard two-drive setup. However this is a ...


7

You can use the command-line iostat tool to monitor disk activity on a per-drive basis. Runnning iostat disk1 disk2 1 will give you an output of disk activity for disk1 and disk2 every second. You'll want to change the disk identifiers to match those of your HDD and SSD. By running this command while you write a bunch of data to your drive (the dd command ...


6

You'll need to partition the drives first, putting the Recovery partition on one of your physical drives. It can't be part of the Fusion drive as its unlikely you can boot directly into a Core Storage logical volume (you need a boot loader separately). Take note of the partition structure in this Ars Technica article about the Fusion drive. The best way to ...


5

Ok so I have solved the problem without re-formatting or re-installing. Hopefully most people won't wind up in this situation. See @robmathers answer for tips on how to avoid deleting your Recovery HD in the first place. WARNING the following commands are fairly low-level and may cause you to loose data. Take proper precautions (backup, clone, etc). But ...


5

I had the same problem after converting a disk. There was a message displayed by diskutil cs convert: Couldn't unmount disk0s4; converted volume won't appear until it's unmounted I solved the problem by unmounting the disk and repairing it : diskutil unmount force disk0s4 diskutil repairVolume disk0s4


5

Aha! The answer comes when you try to deselect the "Encrypt backups" option: So it appears they are one and the same.


5

There is no need to delete the CoreStorage Logical Volume Group. Just resize it: Have a backup! Reboot into Internet Recovery Mode (hold Option-Command-R) as the machine is restarting). You'll eventually be presented with a Max OS X Utilities window. In the menu bar along the top of the screen, click Utilities -> Terminal. At the prompt, enter diskutil ...


5

Your Recovery HD doesn't occupy your whole 3 TB drive. It's disk1s3 in the diskutil listing with the common size of 650 MB. Your Logical Volume Family and the Logical Volume vanished though. To rebuild it start to your Recovery HD or to Internet Recovery Mode, open Terminal and enter diskutil cs list. Copy the LVGUUID To recreate the LV enter diskutil cs ...


4

Depends on your SSD. Some controllers (e.g. SandForce) use compression to lower the number of writes on the SSD. Using encryption generally converts compressible data into a data stream that is farr less incompressible. This ends up resulting in a larger number of writes to the SSD, and consequently will wear it out faster. The compression rates for ...


4

FileVault 2 LVG failures may be irreparable From the manual page for fsck_cs: The fsck_cs utility verifies and repairs CoreStorage logical volume group metadata. ... BUGS fsck_cs does not perform an exhaustive validation, nor is it able to fix many of the inconsistencies that it does detect. Issues with FileVault 1 fsck_hfs (used by Disk ...


4

Ars Technica did an article on how to roll your own Fusion Drive and one that details the layout of an Apple installed Fusion drive from a Mac Mini. From that article: LeeHs-Mac-mini:~ leeh$ diskutil list /dev/disk0 #: TYPE NAME SIZE IDENTIFIER 0: GUID_partition_scheme *121.3 GB disk0 1: EFI 209.7 MB disk0s1 2: Apple_CoreStorage 121.0 GB disk0s2 3: ...


4

According to Anandtech's article Understanding Apple's Fusion Drive: Total volume size is the sum of both parts. In the case of the 128GB + 1TB option, the total available storage is ~1.1TB. The same is true for the 128GB + 3TB option (~3.1TB total storage). If the total size of the storage is the size of the SSD plus the size of the HD, then the HD ...


4

If the SSD fails, the OS won't show you any files and you would need to send both drives to a recovery specialist and expect to get few to some files (and many fragments of files) back. Since the tiered storage moves parts of files to the HDD, there is no guarantee the entire copy of a file will exist on either drive for recovery. Clearly a mostly full to ...


4

I contacted Apple Support and got this solution directly from them. It's a simple fix, actually. WARNING: ONLY FOLLOW THESE INSTRUCTIONS IF YOU HAVE EITHER: Backed up the precious contents of your drive, or... After a thoughtful and deliberate count to 10, decided you couldn't care less about the worthless contents of your drive. Reboot into Recovery ...


4

To expand your CoreStorage Logical Volume Macintosh HD you have to delete the blocking NO NAME EFI partition (disk1s5). The two unnamed parts (138.62 GB and 99.9 GB) are no partitions but unallocated disk space. To remove the second EFI partition (and expand Macintosh HD) you have to boot to Internet Recovery Mode or an OS X system on an external device. ...


4

It is possible to create a Logical Volume Group spanning over more than two disks. I doubt that it will differentiate between fast and slow HDD. The SSD part should work though. To accomplish this put all drives in your iMac and boot to a Mavericks or Yosemite bootable installer thumb drive. Partition all drives as simple volumes with Disk Utility. Then ...


4

I ran into this. In my case it seems the problem was the mac wanted to run a filesystem check on it. After finding the fsck process and killing it, I could then mount the drive properly. $ ps -ef | grep fsck $ kill [pid from above]


3

I set up a Fusion drive using the Terminal utility in the OS X 10.8.2 installer loaded onto a USB thumb drive, after installing an SSD drive as the second drive in my 2011 Mac Mini. This wiped out the data on both drives, but that's what I wanted: a fresh system with a new Fusion drive. If you don't want to save your existing installation, just use the OS ...


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