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harrisonjr98

macrumors 6502
Original poster
Dec 15, 2019
351
203
Hello all, quick question about erasing and reformatting drives on macOS via Disk Utility as someone who recently came back with the launch of Apple Silicon but hasn't used macOS in a while before that!

I'm confused about the hierarchal levels of drive organization in macOS, particularly as it pertains to containers and volumes vs traditional "partitions"? For example of what I'm talking about, this support article details the "levels" of drives in macOS. There's the "storage device," the containers within, and the volumes they contain. I also found two more support articles about partitioning and APFS volume management, but I'm still a bit confused.

So here's what I'm trying to do.

I'm under the impression that basically the entire purpose of containers is to enable smarter volume management with auto-expanding and shrinking volumes based on how much space each of them need. I picked up a new 4TB drive today, aiming to use ~3tb of it as a time machine backup disk and ~1tb to copy-paste backups every month or so from an external drive I use that's formatted as exFAT and thus can't be accounted for by time machine. Assuming there won't be any problems copy-pasting files from an exFAT drive to an APFS one, how would I go about setting up two partitions (err...APFS volumes?) to accomplish what I'm trying to do?

The thing that confuses me the *most* is that ERASING a drive from the "storage device" level asks you to put in a "name" during that process, and applies that name to a volume occupying the full space of the disk inside of a container.
 
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Basically just erase the drive at device level and choose APFS, and name it however you want one of the volumes to be labeled. Then go in and add a volume to the container with the plus button for the other partition. Since APFS shares the total size of the drive you don't have to worry about the size of each volume unless you want to. In your case you can say set a quota for the time machine volume to 3TB that way no matter what time machine is doing you will always have at least 1TB left to drag and drop backup.
 
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