Extend "Macintosh HD" volume with a new, additional disk - ?

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Level 1

4 points

Extend "Macintosh HD" volume with a new, additional disk - ?

Apple M2 Pro Mac Mini

Sequoia 15.3.2

I have an external 1TB disk that I want to add to my existing 1TB Macintosh HD volume to increase space on the boot drive to, ideally, 2TB; I realize there's some overhead that prevents a 1:1 increase. In LWM parlance, I'd be adding LWM slices together to increase the root volume size. Is this possible in Sequoia, or would I be better off leaving the two volumes separate? See the diagram.

Mac mini, macOS 15.3

Posted on Apr 1, 2025 2:17 PM

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Answer 1

Top-ranking reply

MartinR

Level 7

24,137 points

Apr 1, 2025 2:46 PM in response to nyugwai

No easy way to do it, and even if done I consider it too risky to be worthwhile. Macintosh HD is a very complex beast that warrants extreme care. IMHO you should do nothing with Macintosh HD other than install apps and/or perhaps create additional volumes if needed, but that does not increase the available space.

Keep your external drive separate and manage your data accordingly. You do know that you can move most data off the internal drive and continue to operate just fine? For example, I keep my entire photo, music, video & TV libraries as well as Documents & Downloads on an external drive and have never seen any difference in performance vs. having the data on the internal drive.

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Answer 2

tbirdvet

Level 6

17,090 points

Apr 1, 2025 2:35 PM in response to nyugwai

You cannot do that. Just use the external to hold large files like Photos, Music, Movies, etc.. The alt. is to use a larger external as a clone boot drive but then AI will not be available.

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