How to dual boot 2 Mac OS X partitions with Filevault 2

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Level 1

5 points

How to dual boot 2 Mac OS X partitions with Filevault 2

Hi all!

I am trying to do something I've always been able to do without a problem, but doing it with Filevault 2 is tripping me up a bit.

I have 2 paritions on my internal drive. Both have Mac OS X installed -- one has 10.7, and the other has 10.8. Prior to Filevault, I had the option of simply choosing which "startup disk" to boot from, and it would work fine. After enabling Filevault 2, which converted my disk into the whole tree of logical volumes you'd expect, I now have two volumes in 2 volume groups in a volume family (or the other way around, I don't recall what the heirarchy is, but if you follow me this far, you probably know what I mean!).

At one point, if I chose a startup disk in Control Panel, it will let me choose either parition to start up from assuming I've unlocked the target partition. But it ONLY booted from my 10.7 partition. If I restarted and held Option, it ONLY showed me 10.7. So I re-installed 10.8 on my 10.8 partition, and now the situation is reversed. The 10.7 partition is still there (no Filevault, but it's still using Corestorage volumes) and I can choose it in Control Panel, but I can't actually boot from it. I suspect if i re-install 10.7 on that partition it would go back to the original configuration.

Any guidance on how I can properly configure this to boot from both partitions? Preferably with Filevault 2 enabled on both partitions.

Thanks in advance!

-Fred

OS X Mountain Lion (10.8.1)

Posted on Sep 15, 2012 10:11 PM

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Answer 1

Jun 23, 2017 3:54 AM in response to DanTheMan000

Since I posted my question, I've been experimenting and I think I got it work... and it was quite straightforward in the end.

Essentially I partition the already FV2 drive to create a separate partition. I then booted from a USB install drive, and selected the new partition as the target for installing a fresh copy of Mac OS. Install happened without a hitch.

When booting up, I hold down the Alt key and I am presented with 2 HD symbols - one for my original FV2 drive, and the other for my non-encrypted new partition. If I pick the original one, I go straight to the select user and log in screen as it would have before I partition. If I pick the new partition, I get a normal Apple Logo and progress bar and then eventually a request to select the user and to log in.

In my experiments, I also achieved the same end result by starting further back and:-

Format my entire hard disk
Install Mac OS on there and restore from Time Machine backup
Partition to create new partition
Install Mac OS onto the new partition
Go back and turn FV2 on for the original partition

Hope this helps. I'm guessing the issues experienced by earlier posters were resolved by the time 10.11 El Capitan (what I'm using) came out.

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Answer 2

Jun 7, 2017 12:08 AM in response to DanTheMan000

Just wondering if you'd found a solution to this or whether the issue still remains that you can't practically boot from 2 separate OS partitions within a FV2 drive. I'm cionsidering doing exactly this in order to run Mainstage on a separate clean OS install (for performance reasons), on the same Filevaulted Fusion drive I have my "main" OS install on. Want to double check it's worth doing / safe to do so before I go down this route.

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Answer 3

Jun 23, 2017 1:26 AM in response to gggtraveller

I gave up on this idea and removed the second partition.

I've read that filevault work for bootable partitions only. So you'll end up with more than a single bootable partition and thus you'd need a bootloader to select the partition which you want to boot. To this end you might want to investigate in "rEFInd", a bootloader utility for Macputers.

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Answer 4

Linc Davis

Level 10

209,547 points

Sep 16, 2012 8:20 AM in response to fwhipple

I haven't tested your configuration myself, but it seems pretty clear from your description that CoreStorage doesn't support more than one bootable logical volume per logical volume family. It's still in an early stage of development, and many planned features haven't yet been implemented.

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Answer 5

fwhipple Author

Level 1

5 points

Sep 16, 2012 12:54 PM in response to Linc Davis

Hi Linc,

This was my first thought as well, but I really have to question that since it's such a basic function that has been available since ... well forever. It'd also be a big step down in functionality from Filevault to Filevault 2. I know it wouldn't be the first time Apple raised eyebrows with removing obvious functionality (or, I suppose in this case it's more fair to say, not carrying forward previously obvious functionality). I'm just more inclined to think that it must be possible, I'm just not doing it right.

Cheers,

-Fred

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Answer 6

Aug 27, 2015 1:47 PM in response to fwhipple

Actually, it's two CoreStorage volumes, each in its own volume family, both "families" in the same volume group. At least on my system (Yosemite 10.10) where I used "diskutil cs resizeVolume <volume UUID> 100G" to reduce the original Filevault 2 protected system volume to carve out some space for a second volume which I then created using "diskutil cs createVolume <volume group UUID> jhfs+ VolumeNameGoesHere 100%"

After I installed OS X on the second volume, I encountered the same issue as you described. I could only boot the second volume. Only after I unlocked the first (Filevault 2 encrypted) volume manually (using diskutil), I could select it as boot drive and boot the system to it. Now, I can no longer boot to the system on the second (unencrypted) volume.

But I want to be able to boot either of these two systems...

😟

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Answer 7

baltwo

Level 9

62,362 points

Aug 27, 2015 2:17 PM in response to DanTheMan000

Then, you'll have to disable FV2.

27" i7 iMac (Mid 2011) refurb, OS X Yo (10.10.5), Mavs, ML & SL, G4 450 MP w/10.5 & 9.2.2

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Answer 8

Sep 2, 2015 2:07 AM in response to baltwo

That would be disappointing in terms of CoreStorage not supporting basic functions like a OS X dual boot...

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Answer 9

baltwo

Level 9

62,362 points

Sep 2, 2015 1:56 PM in response to DanTheMan000

Could be, but I've five bootable OSs and can't do that with a disk set up for corestorage. It might have some uses, but not for my iMac. The basic issue I have with it is that Apple's moving to force CS on many machines, whether the user wants it or not. Just another move, IMO, to wall off the computer from users and limit what people can do with them.

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