Because
System files and
User/Home files have been separated into separate APFS volumes since Big Sur, it somewhat makes sense to change the way backups are done. This is because:
- System volume is read-only in Big Sur.
- System volume is both read-only and crytographically sealed in Monterey.
This means that
System volume is less likely to be corrupted from malicious applications, accidents, and user negligence.
System volume can still fail due to hardware reasons.
Because the
User or
Home volume is distinct from the
System volume, it means that macOS compartmentalizes the two:
- System volume is one compartment
- User or Home volume is another compartment
We can therefore backup our
User or
Home compartment, which is guaranteed to preserve everything that
we produce and own. The
System volume will contain only that which
Apple produces.
So in the event of the
System volume crashing, we could use the
Recovery process to reinstall macOS on that volume.
But if the whole disk crashes and we lose even the
Recovery partition, then we would need to install macOS from scratch. But just restoring our
User or
Home volume to the new disk might not be enough -- we may need a post-recovery procedure to make macOS recognize the "user ID" of the recovered volume.
Now that the release version of Monterey is installed on my system, I'll see if bootable backups are still working... Will update this post shortly.
Update: Bootable backups are still working with Legacy Bootable Backup Assistant. To ensure that the
System volume is backed up, it's necessary to erase the APFS volume ahead of time.