Migrating 650GB Mac Pro 5,1 boot drive to 2018 500GB Mac Mini

[mavots]

I purchased a 500GB 2018 MM and am migrating from a 2010 Mac Pro 5,1.
The MP5,1 Mojave system and user folder is 650GB in size.
I will migrate the 350GB system files to the internal 500GB SSD and split off the users folder to a separate 1TB external drive.

I tried doing this once already and had no luck. I think it might have something to do with the new T2 chip in the MM. I performed the split as I would on previous Macs but this time it was a no go. Once I linked the system to the new user folder location, the mac would not finish booting. An error message appeared that required my password but pressing enter just kept bringing up the same box over and over. Probably something missing in the users folder.

I ended up erasing the Macintosh HD and starting over. Now my bootable Mojave install flash drive is not being recognized by the MM and I am kind of stuck. T2?

I have cloned the Mac Pro's 650GB Mojave boot drive to a 1TB external SSD. I'm trying to figure out how to make the split work.
Maybe I should first get the external 1TB drive to boot and work properly with the Mac Mini. Then get a second external drive and copy the users folder over to it and then delete the folder from the 1TB drive. Only when that is working properly, clone the system over to the Mac Mini internal drive.
This seems to work for me in the past but I have never had to split off the user files before. Also, the T2 chip may be doing something.

Any best practices for this?
Thanks.

 

[Fishrrman]

IF you've messed up the OS on the Mini, you'd probably do best to boot to internet recovery, ERASE the ENTIRE internal drive, and do a re-install of the OS.

There is a good chance the version of the OS that is on the external drive (from a Mac Pro) WILL NOT boot the 2018 Mini. It might,...
AND... to boot from an external drive, you MUST boot to the recovery partition, and then go to Startup Security and disable everything.

Having said that, there's something wrong when the "system" partition is taking up 350gb. The size of the system and apps (as they ship from Apple) on the new Mini is about 22gb.

I suggest that some "hard thinking" is involved here, to analyze just WHAT is eating up your drive space.

It's also not the best idea to put one's home folder on a drive or partition that is separate from the OS.
It CAN be done, but my advice is NOT to attempt it unless you know exactly what you're doing.

If you have an internal SSD that isn't big enough to hold "everything", I suggest you set it up as thus:
1. The OS (of course)
2. Your applications
3. Stripped-down home folder*

*by "stripped down", you should take the "large libraries" that by default are in the home folder, and move them to an external drive. These are typically the "Photos library" (or library from other pic editing apps), the iTunes music folder, the "Movies" folder, and perhaps the "documents" folder (if a lot is in it).

They can exist on an external drive with no performance penalty.

This can be done with the Setup Assistant when booting and setting up a new Mac for the first time.

 

[mavots]

I was actually able to boot the Mini using the MacPro 5,1 version of Mojave. I erased the internal drive and cloned everything over.
Interesting-the cloned system and user folders are HALF the size of what they is on the MP!
Perhaps some purgeable space was cleared up.

I actually have off-loaded some big files like iTunes and Photos in the past. I think another big one is my Airmail folder which is in the Group Containers folder. I also have a Parallels Windows volume.

So the internal drive is now at about 350GB with everything from the Mac Pro.
I don't like the idea of orphaning the users folder either and will need to be more judicious in what is being stored there.

Perhaps when the next Mojave update comes along I'll do a combo update and everything should align with the Mini. I normally do that anyways.

Big issue now is terrible wifi, both 5 and 2.4GHz. May need to connect an extra Airport Extreme I own via ethernet.

Thanks.