I have a mid-2010 17" MacPro with two internal 1TB SSD drives, running Catalina.

My hope was that I might be able to figure out a way to make them work effectively as one by pointing the "Documents", "Pictures" or "Movies" main folders to wherever I have space, much in same way as you can by setting up preferences in, for example, an app like iTunes. Not being able to do so means I have one SSD drive almost full and the other largely empty.

My question is: Has anyone else found a way to organize files in such a way that the Mac treats the two internal SSD drives effectively as one?

  • 2
    Firstly, welcome to Ask Different! :) A few questions for you. Is it mainly the Photos app taking up space in your Pictures folder? And what's mainly taking up space in your Movies folder? Finally, are you comfortable using Terminal?
    – Monomeeth
    Commented Mar 3, 2021 at 5:00
  • Thanks for the weclome! It's pretty much an even mixture of photos, docs and various types of movie files. I don't think I want to go near Terminal, especially since I'm already pushing the outer limits of an old Mac and running Catalina on an unsupported Mac. :-)
    – Alex
    Commented Mar 4, 2021 at 6:22

2 Answers 2


You can set Photos.app to have its library at a given location in its preferences.

As for Documents: there's nothing to stop you just storing all (or some) of your documents on a folder on another drive. You can even put a folder in the Finder sidebar to the location to make it easy to navigate to.

Files don't need to go in the Documents folder, and there's nothing special about it (apart from annoying security requests in Catalina and up).

  • You can also use a symlink or alias within Documents to point to a folder on another drive.
    – nohillside
    Commented Mar 3, 2021 at 11:35
  • Thanks for this! It seems I may have been overthinking the problem. I'll give it a try. Cheers!
    – Alex
    Commented Mar 4, 2021 at 6:28

I haven't tried this myself but you should be able to create an APFS volume group from your two drives to effectively create one "Fusion" drive. You would use

sudo diskutil apfs create


sudo diskutil apfs createContainer

to accomplish this. You can run those commands as-is to read usage. Also see the manual page for diskutil (man diskutil).

The advantage of a Fusion drive is that you don't have to manually manage which files get put onto which drive; the whole thing behaves like a RAID 0 array (i.e., JBOD, "Just a Bunch of Disks"). The downside is that you're now multiplying your chances of total data loss if there's corruption on either of the drives. So before beginning, you are very strongly advised to create AND maintain a backup of your data.

  • Thanks very much for your answer. Sounds a little risky and I'm a guy with a low risk tolerance. :-) I might come back to this if no other simpler solutions present themselves. Many thanks again!
    – Alex
    Commented Mar 4, 2021 at 6:25
  • @Alex Absolutely. Though, to play devil's advocate: If you are indeed risk-intolerant, then you presumably already have a well-established backup system in place and are prepared for the (inevitable!) failure of either one of your drives :-)
    – pion
    Commented Mar 4, 2021 at 6:35
  • Point taken, and yes i have back ups of back ups. I'll see how things go trying to arrange the folders as suggested below and if that doesn't work I'll circle back on this. Many thanks again!
    – Alex
    Commented Mar 4, 2021 at 6:38

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .