MBP Dual boot issue

[multimania]

Hi all, I have a 2017 mbp 16" 1tb machine. Whilst it's main work has been transferred to my Mac Studio, I still use it and the battery has been replaced so it's worth hanging onto (at least for me).

Recently I created a new "volume" and installed Ventura alongside Mojave. Mojave was kept due to legacy software that I thought I'd still need. However the more I use Ventura which works quite nicely on it, the more I feel like removing the Mojave volume – but...

I'd like to understand if I have a backup of the Mojave volume (which I do), is it relatively easy enough to create a volume in the future and restore this volume from an external ssd. I have a full ssd backup so I'm kind of thinking it could work. My hesitation is that I see that the volumes on the internal ssd are dynamically resized according to use and so I wouldn't want it not to be possible to restore. The backup I have is a bootable one from Carbon copy cloner.

Any ideas would be much appreciated.

Cheers.

 

[Fishrrman]

You already have a cloned backup of the Mojave volume, created via CCC?

Does it boot?

If it does, well, that's really "all you need".

If you choose to remove it from the MBP, you might consider making a "clone of the clone" on a second drive. Reason why: if the existing external boot drive fails, you'll need that "second copy"...

 

[Brian33]

I'd like to understand if I have a [CCC bootable] backup of the Mojave volume (which I do), is it relatively easy enough to create a volume in the future and restore this volume from an external ssd.

I can't answer definitively because I haven't tried that, but from what I understand of CCC, Mojave, and Ventura, it seems to me that such a restore to a new volume should work fine.

Recently I created a new "volume" and installed Ventura alongside Mojave.

I'm assuming your new volume for Ventura was created in the same Container that the Mojave volume was (is) in. You're wondering if you delete the Mojave volume now, could you later create a new volume in that container, and restore Mojave from your CCC backup to that new volume (and have it bootable).

I think it should work, but if your internal storage is big enough, I'd recommend trying it before you delete your Mojave volume. Just create yet another volume (call it "Mojave2") for a second copy of Mojave, and try restoring your backup to the new Mojave2 volume, without touching your current Mojave volume. Can you boot to the newly-restored Mojave? If so, you'd be free to delete both Mojave volumes, knowing that the restore process works.

If your internal storage isn't big enough for all three volumes (Ventura, Monterey1, and Monterey2) I think you could exclude a lot of user data during the test restore for Monterey2, and still be confident that your hypothetical future restore would work.

Or, as @Fishrrman points out, maybe being able to boot Monterey from the external drive is good enough for your future self!

 

[multimania]

You already have a cloned backup of the Mojave volume, created via CCC?

Does it boot?

If it does, well, that's really "all you need".

If you choose to remove it from the MBP, you might consider making a "clone of the clone" on a second drive. Reason why: if the existing external boot drive fails, you'll need that "second copy"...

Hi @Fishrrman, thanks for your reply. Yes the backup os on a Samsung T7 and I've tested it several times (booting from it). Good idea re: having a backup of that drive. I mean, it does have a shed load of music software/plugins on it so It would be a royal pita if I never had access to it again, despite not using it all the time.

 

[multimania]

I can't answer definitively because I haven't tried that, but from what I understand of CCC, Mojave, and Ventura, it seems to me that such a restore to a new volume should work fine.


I'm assuming your new volume for Ventura was created in the same Container that the Mojave volume was (is) in. You're wondering if you delete the Mojave volume now, could you later create a new volume in that container, and restore Mojave from your CCC backup to that new volume (and have it bootable).

I think it should work, but if your internal storage is big enough, I'd recommend trying it before you delete your Mojave volume. Just create yet another volume (call it "Mojave2") for a second copy of Mojave, and try restoring your backup to the new Mojave2 volume, without touching your current Mojave volume. Can you boot to the newly-restored Mojave? If so, you'd be free to delete both Mojave volumes, knowing that the restore process works.

If your internal storage isn't big enough for all three volumes (Ventura, Monterey1, and Monterey2) I think you could exclude a lot of user data during the test restore for Monterey2, and still be confident that your hypothetical future restore would work.

Or, as @Fishrrman points out, maybe being able to boot Monterey from the external drive is good enough for your future self!

Hi @Brian33, thanks a lot for your answer.

From my understanding the Ventura volume is a separate entity. I've made a screenshot below. It's a good idea to create another volume and attempt a restore, unfortunately space won't allow for it. The Mojave section is around 750gb and the Ventura one is the rest. This is my primary reason for considering doing this. There's about 200gb actual free space give or take and I don't want to wear the internal ssd any more than necessary at this stage in it's life.

The option to just use the backup Samsung T7 is a possibility. I mean I know it's slower but it would primarily be for accessing old projects etc.

Thanks.

 

[Brian33]

It's a good idea to create another volume and attempt a restore, unfortunately space won't allow for it.

Yes, I see.

From my understanding the Ventura volume is a separate entity.

It's a little hard to tell (see below) but it looks like the "Lilly" volume is in the same Container as "Ventura volumes", which I think is a Volume Group. IIRC Mojave did not use Volume Groups -- that came to macOS later, so this makes sense.

If you care to, you can clarify the setup to yourself by going to the View menu item in Disk Utility, and selecting "Show All Devices" (instead of the default, which is "Show Only Volumes"). Then you can select any line in the left pane and the top of the right panel will tell you if it's a Physical Device, Container, Volume Group, or Volume.