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GoldenChild

macrumors 6502a
Original poster
Jun 3, 2014
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I upgraded to OS X Yosemite yesterday and I noticed this under disk utilities... I noticed that I had two "Macintosh HD" drives. I didn't notice this in OS X Mavericks. I hope this isn't a stupid question, but I hope I can get some answers. Thanks!
kYaGmfZ.png
 
Yes, been that way since forever. Top one is the physical drive, the one(s) below it are the partitions.
 
Yes, been that way since forever. Top one is the physical drive, the one(s) below it are the partitions.
Thank you man, so don't even bother to do anything right? Haha. I was freaked out for a bit.
 
Strange. No issues here.
 

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I upgraded to OS X Yosemite yesterday and I noticed this under disk utilities... I noticed that I had two "Macintosh HD" drives. I didn't notice this in OS X Mavericks. I hope this isn't a stupid question, but I hope I can get some answers. Thanks!
Image

You have Filevault encryption turned on and with FV on, that is how the disk looks in Disk Util. This is not new to Yosemite. You just did not notice it before.

Here is mine with FV on in Mavs.

surgR3K.png


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Yes, been that way since forever. Top one is the physical drive, the one(s) below it are the partitions.

Only if you have Filevault encryption turned on.
 
Since update I have two Macintosh HD - Previously it was name of the actual drive you had installed.
 
Do you have Filevault encryption turned on like the OP? If you do, that is normal and existed before Yosemite.

Nope - as I said it sonly changed since update, doesn't bother me though.

However I thin it may be a bug I have like 150GB of 'free space' that I can't format or do anything with lol - will have to try sort out after full release.
 
Specifically it's a trait of having CoreStorage volumes, which is how FileVault works.

If you have a fusion drive it'll probably do the same.
 
I don't have FileVault on, but I've always had the drive show up twice like that. Since SL as far as I can remember.
 
Which reminds me that Disk Utility has never changed since I can remember. I've been a Mac user since 2006, almost 10 years old, if not more.
 
I have an entirely different issue, but didn't feel like making a new thread. I'll post a photo in a while.

I created a new partition on my SSD with Disk Utility like usual for the previews, installed 10.10 to the new partition, and after playing with it, rebooted back to mavericks. Now here's where the issue starts. My drive shows up as a logical volume with my two partitions, one Mavericks, one Yosemite. But, I cannot edit, resize, or delete either of them. Normally after playing around with it for a while, I delete the partition I installed the preview on. But the option is grayed out. This happens from the recovery partition as well as booting from a Mavericks USB drive. Not sure what's up?

Anyway, on to this topic, here's how it looks in Snow Leopard, since I'm using my BlackBook for the time being...
kkN1aJu.png


Screen Shots:
Partitions
GOzaGE3.png


SSD:
dG9mcny.png


Yosemite:
b3fm6mR.png


I can see that Yosemite is a volume by it's mount point, but I just want to get rid of it...
 
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I have an entirely different issue, but didn't feel like making a new thread. I'll post a photo in a while.

I created a new partition on my SSD with Disk Utility like usual for the previews, installed 10.10 to the new partition, and after playing with it, rebooted back to mavericks. Now here's where the issue starts. My drive shows up as a logical volume with my two partitions, one Mavericks, one Yosemite. But, I cannot edit, resize, or delete either of them. Normally after playing around with it for a while, I delete the partition I installed the preview on. But the option is grayed out. This happens from the recovery partition as well as booting from a Mavericks USB drive. Not sure what's up?

Anyway, on to this topic, here's how it looks in Snow Leopard, since I'm using my BlackBook for the time being...

It says logical volume group when you have that top Yosemite selected, and that leads me to believe you turned on Filevault in Yosemite. If you select the lower Yosemite does it say Encrypted Logical Partition for Format: in DU.

Enter the command below in Terminal and post up the output.

Code:
diskutil list
 
It all seems to stem from core storage and Yosemite seems to be using it differently than past releases. I don't use fire vault, and It's not a fusion drive. Just an SSD in the optical bay, and my HDD. I'll have to read up on it as I haven't really looked into it all that much.

Here's what diskutil put out.


It's not a huge deal, because I'll probably do a full reinstall when the public beta comes out anyway, and again when the final release is out. Since my data is on my HDD it's unaffected. But it's still interesting.
 
It all seems to stem from core storage and Yosemite seems to be using it differently than past releases. I don't use fire vault, and It's not a fusion drive. Just an SSD in the optical bay, and my HDD. I'll have to read up on it as I haven't really looked into it all that much.

Here's what diskutil put out.

It's not a huge deal, because I'll probably do a full reinstall when the public beta comes out anyway, and again when the final release is out. Since my data is on my HDD it's unaffected. But it's still interesting.

This is odd. That is making the new Yosemite partition look just like a Fusion logical volume. Look at this post of a DU with Fusion. Although your diskutil list output is different than a true Fusion drive.

So in Mavs you just shrunk the main volume then added the new one at the bottom, then installed Yosemite to the new volume?

You should be able to kill that Yosemite volume with the "diskutil cs delete" command. Run "diskutil cs list" to ID the UUID of the volume. Give this a read. It describes how to kill a Fusion volume, but the same steps will apply to killing that core storage volume.

Make sure you have a good backup first in case this goes sideways. :eek:

Edit: Forum member BrettApple was kind enough to capture the Terminal commands he used in his post here showing the steps I described above.

From Brett's screenshot below you can see how he used "diskutil cs list" to find the correct volume UUID to kill then ran "diskutil cs delete" with the UUID to remove the Yosemite core storage volume. Afterwards Disk Utility can be used to expand your main partition into this now empty space.

YdrNA5K.png


EDIT2: Much simpler method... if you installed Yosemite on the first drive in your Mac, running the command below will turn off the core storage.

Code:
diskutil cs revert disk1
 
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For what it's worth, this happened to mine also. I shrunk my main Mavericks volume and created one just for Yosemite. After the install it's showing just as the OP (like a FileVault or Fusion drive logical volume) except with two partitions.

It's worth noting that this happened on my machine with an SSD and a HDD in the optibay.

I've also installed the beta on another machine with only a single SSD and it did NOT do this odd volume management.
 
For what it's worth, I have a 2012 MBA with just one SSD installed, nothing else, and I got the same problem.

I shrunk my Mavericks partition and created a new clean partition on which to test Yosemite. The result is this:
 

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Perhaps this means that Yosemite now partitions all HFS volumes (or at least system volumes) with Core Storage by default? I wonder if there are new Core Storage features we haven't heard of yet that might suggest why they're doing this? I have my fingers crossed for data integrity features, but I would have thought they'd have mentioned that somewhere.

It could be a change to get rid of the need to restart to enable FileVault encryption actually, as having the volume as Core Storage already should mean it can just store the key(s) and start encrypting right away.
 
Perhaps this means that Yosemite now partitions all HFS volumes (or at least system volumes) with Core Storage by default? I wonder if there are new Core Storage features we haven't heard of yet that might suggest why they're doing this? I have my fingers crossed for data integrity features, but I would have thought they'd have mentioned that somewhere.

It could be a change to get rid of the need to restart to enable FileVault encryption actually, as having the volume as Core Storage already should mean it can just store the key(s) and start encrypting right away.

What is odd though is it only seems to do this for people that install on a second partition. I have not seen any reports of this happening when Yosemite is installed on the only partition on a drive like would be the more common setup for a user.
 
I have a similar setup now and I did not change my partition scheme.

I did, however, upgrade over my Mavericks install.

This is my 'diskutil list' output:

Code:
/dev/disk0
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *256.1 GB   disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:          Apple_CoreStorage                         255.2 GB   disk0s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3
/dev/disk1
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                  Apple_HFS System Drive           *253.4 GB   disk1
                                 Logical Volume on disk0s2
                                 A4128CCA-0DC8-4EC3-93F3-A1DEF0FFE1E8
                                 Unencrypted

Disk Utility shows:
System Drive​
System Drive​
 
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