Confused by this on APFS? So you should be, as it’s complicated by features like snapshots, sparse files, and the file system itself. There’s no single figure.
APFS
For many users, it’s essential to be able to check the integrity of the data which are in a backup. This feature has changed when backing up to APFS.
Tired of HFS+? Disenchanted by APFS? Why not copy or back up to a different file system? Here are crocodiles waiting to bite you.
How APFS, the boot volume group, hashes, and Secure Boot all combine to guarantee the integrity of your system, and save you trouble and work.
The differences between HFS+ and APFS volumes explored. What a container is, and how to add new HFS+ and APFS volumes to a disk.
Tackles decisions and problems, including whether to use APFS in the backup sparsebundle, AFP or SMB, and configuration.
Can you migrate your old backups from HFS+ to APFS format? What can slow your backups down? Can you still use AFP, and what about restoring the system?
Links to my presentation, and to a selection of useful articles about Time Machine backups to APFS, and more.
An exploration of how Time Machine backs up to APFS, using Mints to make log access quick, simple, and easy to understand. And notes on changes in Monterey.
Why deleting either the System or Data volume, but not the whole Volume Group, could get your Mac into trouble in macOS 11 or 12.
The Eclectic Light Company 