Delete CoreStorage Volume even as OS X won't acknowledge there is one?
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04-10-2020 - |
Question
I installed Yosemite on an external 3TB drive. I made a specific 300GB partition on it to hold the system and a second for data. Installation worked fine. However, according to Disk Utility in both Mavericks and Yosemite there is only a little more than 800GB available on the whole disk.
When I run diskutil list; echo; diskutil cs list
it says there are no CoreStorage Volumes, but I knew from the Yosemite installation that there is one.
How can I get rid of the CoreStorage Volume even as OS X won't acknowledge there is one? Do I dare to delete and erase the complete drive from Disk Utility in Mavericks? It seems risky as it can't even show me the lost partition space.
Here's the output:
/dev/disk2
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *801.6 GB disk2
1: EFI EFI 209.7 MB disk2s1
2: Apple_HFS X Drive 320.1 GB disk2s2
3: Apple_Boot Recovery HD 650.0 MB disk2s3
No CoreStorage logical volume groups found
Solution
I ran the command cat /dev/random > /dev/disk2
as user "su" and all partitions are gone now. At first, the available disk space was still only 801GB. After a while it showed up properly in Disk Utility as 3.0TB though and I was able to reformat it. Excellent!
Thanks to Topher Kessler for posting the proper commands in How to fix deep formatting problems with OS X drives!
CoreStorage is great technology. Apple info still leaves a lot to be desired.