MacOS – Why does the 3TB Seagate HD keep formatting as a Logical Volume Group

core-storagedisk-utilityhard drivemacospartition

This is really annoying. I have a brand new Seagate 3TB 7200 RPM hard drive that I am trying to format/partition in Disk Utility. Every time I change any settings or erase the drive, it changes it to a Logical Volume Group and subsequently changes the partition to a Logical Partition. Then I have to use Disk Utility in terminal and manually erase it.

This is really weird because I have two of these exact same drives and I zeroed out and partitioned the first one a couple of months ago without any issue whatsoever. I am not doing anything different than I always do when setting up my HDs.

I'm running OSX 10.8.4 on a 2009 Mac Pro.

Edit:
I am not trying to make a Fusion Drive. The drive will be partitioned as GUID Partition Table with 1 partition and Mac OS Extended (Journaled) and then when I erase the drive or change the number of partitions, or the partition map—any of these adjustments makes it instantly a Logical Volume Group. Again, to clarify, this is ONE drive, I shouldn't be able to make it a fusion.

Best Answer

I also have this issue... MacPro, 3TB drive (Seagate). I have to use the terminal:

diskutil list
diskutil unmount /dev/disk22
diskutil eraseDisk HFS+ "Macintosh HD" /dev/disk22

etc etc to utilize this drive correctly. (Sorry for all the commands. Posting them just in case it helps someone. Though anyone using those commands better know what they do first!)

Related Solutions

MacOS – Unable to reformat/repartition CoreStorage logical volume (Fusion drive)

I was able to delete a mess I made trying to delete my Raid 10 in diskutil (which ended up looking similar to above) using the commands below in Terminal.app. May or may not work with fusion but it's easier than booting up again.

Get rid of the volume - copy paste the logical volume name where it says "Logical Volume Name", without the quotes:

diskutil cs deleteVolume "*Logical Volume Name*"

Free the disk - copy paste the volume name where it says "Physical Volume Name", without the quotes:

diskutil cs removeDisk "*Physical Volume name*"

Repeat these steps as needed.

MacPro Hard Drive 3 TB or Larger formatted to Logical Volume Group by Disk Utility

This problem has been reported to occur on Intel MacPro's using internal drives from various manufactures with capacities >= 3 TB. Specifically, it's been reported when using Disk Utility in OS X Mountain Lion (10.8) and Mavericks (10.9).

Although there have been solutions involving using diskutil in Terminal posted here at AskDifferent and elsewhere on the web, I found a simpler solution: Format the disk using Disk Utility from an OS X Snow Leopard (10.6) Install DVD.

Warning: This solution will cause you to lose all data on the drive.

Backup any valuable data from the drive in question.
Reboot using the OS X Snow Leopard (10.6) Install DVD. (Hold down the C-Key to boot from the DVD.)
Choose your language (eg. English).
Instead of installing OS X, choose Disk Utility from the Utilities menu.
Select your drive from the pane on the left of the Disk Utility screen.
Choose the Partition tab.
Select your desired Partition Layout.
Select Mac OS Extended (Journaled) under Format:
Check the Options button and verify that GUID is selected as the partition scheme.
Click the Apply button and verify you want to proceed.
When the partition and format process is complete, quit Disk Utility and reboot.

The disk will now be correctly formatted using a GUID partition table.

(If you need to repartition or reformat the drive in the future, you will need to repeat this process. Hopefully Apple will fix this bug in a later version of Disk Utility.)

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