Can you use an APFS-formatted Mac with a pre-APFS Apple Time Capsule?

Question

I'm thinking of upgrading to macOS High Sierra, however I'm a bit cautious with the APFS, also because it just came out.

Are you able to use Time Machine on a Mac with APFS-formatted disks with an Apple Time Capsule that uses an HDD an older file system (HFS+)

My guess is it won't work so you have to also manually convert the Apple Time Capsule to APFS.

Answer 1

Having an APFS-formatted system backed up to an HFS+ Time Machine/Time Capsule disk is actually the currently intended use case. The current version of Time Machine supports APFS only as a source disk, not as a destination. In fact, if you format your Time Machine backup disk to APFS, Time Machine will re-format it back to HFS+ before using that disk. This was discussed in WWDC 2016, and appears to still be true.

APFS does not support directory hardlinks, a feature of the filesystem used by Time Machine. Until Time Machine is rebuilt to take advantage of APFS features (like snapshots) instead of hard links, APFS won't be usable as a destination disk.

Also, I personally just backed up my APFS laptop to my usual HFS+ backup disk via Time Machine, so there is some empirical validation.

Answer 2

Yes, you can use a normal Time Capsule that is not APFS-formatted with APFS-formatted disks.

APFS and Time Machine

You don't need to change any Time Machine settings to back up APFS-formatted disks. Any Time Machine share points must be shared over SMB instead of AFP.

Source: Apple.com

This applies to Apple’s TimeCapsules as well. They are just network attached hard drives with Wi-Fi routers made by Apple.