CORRECTED VERSIONMy experimentation with
Partitions and
Containers has so far revealed...
- PARTITIONS:
- Are applied at the device level
- Always have a fixed size that is set in the disk partition map.
- Contain one volume
- That volume may be formatted Mac OS Extended (HFS+), FAT, EXFAT, or APFS
- If the Partition is formatted APFS, it will have one Container and one or more APFS volumes in that Container
- CONTAINERS:
- Are applied at that Partition level
- May have one or more "APFS Volumes" sharing the same space.
- Volumes in a Container may only be formatted APFS
- These volumes may expand and contract dynamically as needed and the only limit on the capacity of these volumes is the size of the Container.
- DISK UTILITY:
- IMHO the GUI needs work
- CAUTION: After partitioning/re-partitioning a device or adding a Volume it is necessary to quit and restart Disk Utility to refresh the display and get accurate information. At least that is true in Disk Utility 17.0.3.
- CONCLUSION:
- Containers overcome most, if not all, of the limitations of partitioning
- "Volume" and "APFS Volume" are bound to create a LOT of confusion among the less technically inclined and even among the very technically inclined unless they are carefully differentiated.
- As soon as I can resuscitate my test HDD I will verify that this works on HDDs as well as SSDs
As good and clear an analysis as that is, I agree that myriad users will still find it confusing, but for what it's worth, it ties in with my experience.
(*)I'll add that APFS volumes can be added to my
flexible volumes container at will.
I'll also add that as opposed to the 150 MB used by an empty 50 GB HFS+ partition or the350 MB used by an empty 300 GB partition, an empty APFS volume uses only 90 KB of space.
(*) My Disk Utility experience differs from yours: I just added and deleted an APFS volume to/from my one container, and both actions were reflected immediately by Disk Utility Version 17.0.3 (1646).
More: I agree that Disk Utility's GUI needs work, but I also think that much of what's wrong with it is our unfamiliarity with the new info it's displaying. If it's all APFS, it's not too bad, but when you've got APFS containers and volumes, and HFS+ volumes in the same sidebar it gets confusing.