Reclaim partition and core storage

[robgendreau]

I have an external drive with two partitions. One was a clone of Mavericks; I just erased that drive and figured I'd merge the partitions (.5 and 2.5 TBs).

But I notice that now I seem to have both logical and physical volumes of that .5TB; somehow that volume got core storaged.

I cannot now resize the 2.5TB partition to 3TB, merging the empty .5. Disk Utility does, however, give me the option to merge the 2.5 up, but I believe that would destroy the data.

So, do I have to use diskutil revert cs on the logical .5 to be able to subsequently merge it? some other way?

 

[mikecwest]

I have an external drive with two partitions. One was a clone of Mavericks; I just erased that drive and figured I'd merge the partitions (.5 and 2.5 TBs).

But I notice that now I seem to have both logical and physical volumes of that .5TB; somehow that volume got core storaged.

I cannot now resize the 2.5TB partition to 3TB, merging the empty .5. Disk Utility does, however, give me the option to merge the 2.5 up, but I believe that would destroy the data.

So, do I have to use diskutil revert cs on the logical .5 to be able to subsequently merge it? some other way?

Yes, you need to revert it to logical from core storage. After that you should be able to delete the unwanted partition. (Make sure you delete the right one)

If the one you want to keep is the FIRST partition, you should be able to drag the partition to the end, using Disk Utility.

If the one you want to keep is the SECOND (or subsequent) partition, you can not drag it UP in the disk utility to add that space.

I am sure there is some terminal command that might be able to do it, but its not as easy in that case. If you have iPartition, it will be an easy task. Use caution, some apps may have issues, however most will not. An example is Dropbox, lets say you have a dropbox account in which you do not know the password (I'm not going into details on this, but some people are in that situation for legitimate reasons). If that is the case, your drive's UUID may change, and dropbox will de-authenticate you. Additionally, some apps may use your UUID for registration, and may have to be re-registered. Most developers will offer some way to rectify this, however, some developers may not.

None of that should apply to the FIRST situation, when using Disk Utility to "drag the partition down" to include the remaining space.

 

[Weaselboy]

So, do I have to use diskutil revert cs on the logical .5 to be able to subsequently merge it? some other way?

Yes... run the command below in Terminal with the drive attached and post up the results and I'll try and help you out.

diskutil cs list

 

[robgendreau]

I already ran diskutil cs list; given the response here I need to know what arguments to use with diskutil cs revert, or if it would even work.

BTW, the logical volume that I am seeking to delete has the following entry:

+-> Logical Volume etc
---------------------------------------------------
Disk: disk4
Status: Online
Size (Total): 500229472256 B (500.2 GB)
Conversion Progress: -none-
Revertible: No​

It appears that the logical volume group is ONLY this partition; in other words, there is a 3TB drive with a 2.5TB partition that is not listed as core storage, and a .5TB partition that is core storage (with one logical volume filling the entire .5 physical volume). So it isn't revertible, since it isn't part of any other logical volume group.

Can I just erase it and reformat it so it isn't a core storage volume group?

 

[Weaselboy]

I already ran diskutil cs list; given the response here I need to know what arguments to use with diskutil cs revert, or if it would even work.

BTW, the logical volume that I am seeking to delete has the following entry:

+-> Logical Volume etc
---------------------------------------------------
Disk: disk4
Status: Online
Size (Total): 500229472256 B (500.2 GB)
Conversion Progress: -none-
Revertible: No​

It appears that the logical volume group is ONLY this partition; in other words, there is a 3TB drive with a 2.5TB partition that is not listed as core storage, and a .5TB partition that is core storage (with one logical volume filling the entire .5 physical volume). So it isn't revertible, since it isn't part of any other logical volume group.

Can I just erase it and reformat it so it isn't a core storage volume group?

That won't revert, but you can delete it.

I was wanting the output so I could see the UUID of the logical volume to delete. It would be like this with that long UUID in place of the word UUID.

diskutil cs delete UUID

If there is nothing else on disk4 you want you can do this.

diskutil cs delete disk4

 

[robgendreau]

That won't revert, but you can delete it.

I was wanting the output so I could see the UUID of the logical volume to delete. It would be like this with that long UUID in place of the word UUID.

diskutil cs delete UUID

If there is nothing else on disk4 you want you can do this.

diskutil cs delete disk4

Ah, great. But if I delete it, what am I left with? Can I just expand the second physical partition to include it?

EDIT: Yikes, just read the man for diskutil cs deleteLVG and diskutil mergePartitions. The problem is that apparently using mergePartitions thereafter will erase the second partition. That's the stuff I want to keep. So even though deleteLVG will erase it, I still can't get where I wanna go. So probably a reformat and copy the stuff back will be the best option. Longer, but safer.

BTW, I have reformatted partitions on two external drives since installing Yosemite. One drive with one partition got no CS. The second, the 3TB with two partitions, ended up with the reformated partition as CS. Does Disk Utility do this by default when you reformat a partition as opposed to the whole drive? I didn't see any settings or choices in this regard.

 

[Weaselboy]

Ah, great. But if I delete it, what am I left with? Can I just expand the second physical partition to include it?

Yes. It will just be unpartitioned space.