Revert the core storage!

[tywebb13]

Reverting core storage still works in Sierra.

If the installation creates a core storage logical volume you can revert it to get partitions back to normal by running these 2 commands in terminal.

diskutil cs list

and then

diskutil coreStorage revert lvUUID

where lvUUID is the last lvUUID reported by the previous Terminal command.
Then restart for everything to get back to normal after you have run these commands in Terminal.

This is good if you want the recovery partition to show up in the startup manager you get when booting up with the option key.

 

[blasto2236]

Forgive me for being a layperson, but can you describe in plainer terms what this means? I noticed I don't have a recovery partition after wiping my SSD and reinstalling El Cap a few months ago and would love to have this back, if that's what this does. And would it be an El Cap or Sierra partition?

 

[tywebb13]

Core storage is a logical volume management system layer between the disk partition and file system.

OS X installers introduced it starting with yosemite, then el capitan and now sierra. It won't install core storage in all macs, but will on quite a few of them.

The recovery partition will be hidden from the startup manager if core storage is present.

You can still boot up the recovery partition with cmd R even if core storage is present and this does not require a revert.

But if you want the recovery partiton to show up in the startup manager, you'll have the revert the core storage. This is especially so if you dual boot multiple systems.

If you reinstalled el capitan you should have an el capitan recovery partition.

 

[grahamperrin]

Looking ahead: where Core Storage is a default, it may be prudent to accept that default.

(Note to self: discover whether Apple File System converter will benefit from, or require, Core Storage.) – done.

 

[tywebb13]

Looking ahead: where Core Storage is a default, it may be prudent to accept that default.

(Note to self: discover whether Apple File System converter will benefit from, or require, Core Storage.)

No and no.

Core storage is not a default necessarily. As I said before it isn't installed on all macs.

Encryption relies on core storage in hfs+, not in apfs.

In any case if ever you want core storage back again it is easy to do with the convert command.

 

[grahamperrin]

Thanks. I need to listen to, or review, parts of the WWDC session (on a different computer, one that's compatible with Apple's stream). – done.

No and no.

@tywebb13 please see the postscript at https://forums.macrumors.com/posts/23016166

 

[Weaselboy]

Core storage is not a default necessarily. As I said before it isn't installed on all macs.

With Yosemite and up it is the default if you meet these three conditions.

1. Machine is a portable
2. CPU supports AES
3. No Bootcamp partition present

 

[tywebb13]

Thanks. I need to listen to, or review, parts of the WWDC session (on a different computer, one that's compatible with Apple's stream). – done.



@tywebb13 please see the postscript at https://forums.macrumors.com/posts/23016166

I'm not going to do a convert back to core storage just because of apfs.

The apfs conversion won't actually require core storage. It will just read it in case it is present as part of the conversion process.

I'll have to have a better reason to convert back to core storage. And as I said before if any such reason arises then it is easy to do with the convert command.

With Yosemite and up it is the default if you meet these three conditions.

1. Machine is a portable
2. CPU supports AES
3. No Bootcamp partition present

And that thing about AES - really all it does is make encryption faster. If you don't worry about such things then the core storage is quite unnecessary.

So happy to leave it in it's fully REVERTED state for now.

 

[grahamperrin]

… that thing about AES … If you don't worry about such things …

Not a worry; it's simply one criterion of the three that are/were associated with Core Storage as a default.

@tywebb13 I'm not asking you to now convert to Core Storage. Rather, I'm observing what was written at WWDC about future use of Apple File System converter with Core Storage.

 

[tywebb13]

Yes. It is probably more a discussion for macOS 10.13, not 10.12.

But all the points I made will still be true of 10.13 unless apple remove the ability to revert the core storage (which they probably won't do).