ASIF disk images are new in Tahoe, and promise to be space efficient, as they’re sparse files, and almost as fast as the disk they’re stored on. Ideal for VMs and general use.
diskutil
What separates System and Data volumes, and how does macOS know they’re part of a boot volume group? What distinguished backup volumes, and what is Sidecar?
How to tell whether someone has been eating the (APFS) porridge on one of your disks, using Get Info and DiskUtility’s First Aid. And a surprise hidden volume from 3 years ago.
APFS or HFS+? Which can Time Machine back up to? What about hard disks? Which format for use on PCs? And which are supported by Disk Utility now?
This reference covers fsck_apfs, diskutil information, diskutil apfs, conversion of HFS+ to APFS, mount_apfs, and newfs_apfs.
What’s in APFS, and what are its tools? How to interpret the version number, and what do we know has changed with different versions? How compatible are they?
Repairing permissions has a long history in Mac OS X. The permissions concerned have changed over the years, and it’s no longer what it once was.
Here’s an APFS (Encrypted) volume that isn’t encrypted, and an unencrypted volume with FileVault active. Something must be wrong.
Should you run First Aid on every volume, then each container? And why can it return status 65? How can you work around that?
Once, you could run diskutil to ‘fix’ broken permissions in your Home folder, then it was replaced by repairHomePermissions in Recovery. Apple no longer documents this, but it’s still there. Should you use it?
The Eclectic Light Company 