APFS preparation and macOS High Sierra

As part of the pre-release announcements about macOS High Sierra, Apple released the following KBase article:

• Prepare for APFS in macOS High Sierra: https://support.apple.com/HT208018

Apple makes a number of statements about APFS and its effects in this KBase article, but what do they all mean? I’m going to try to clarify while staying on the right side of Apple’s NDA. For more details, see below the jump.

APFS conversion criteria

• Question: What kind of drives will be converted to APFS?
• Answer:

• Question: If the drive qualifies, is the HFS+ -> APFS conversion automatic when I upgrade to High Sierra?
• Answer: Yes

APFS compatibility

• Question: Can you read and write to an HFS+ formatted drive while booted from an APFS formatted drive?
• Answer: Yes

• Question: Can you read and write to an APFS-formatted drive while booted from an HFS+ drive?
• Answer:
  • On macOS High Sierra and later: Yes
  • On older versions of macOS, OS X and Mac OS X: No

APFS and FileVault

• Question: Can a FileVault-encrypted drive be converted to APFS as part of the the macOS High Sierra upgrade process?
• Answer: Yes. If the drive qualifies for the conversion process, the encrypted drive will be converted from HFS+ to APFS as part of the macOS High Sierra upgrade process.
  • As part of the conversion process, the encrypted Core Storage volume will be removed from the drive and the drive will have APFS’s native encryption activated.

APFS and Boot Camp

• Question: Can I run Windows using Boot Camp on an APFS boot drive?
• Answer: Yes. However, Windows will not have the necessary driver support to read or write to APFS formatted drives.

APFS and file sharing

• Question: Can I enable AFP file sharing to share directories stored on an APFS drive?
• Answer: No. SMB file sharing will need to be used.

• Question: What file sharing protocols can share directories stored on an APFS drive?
• Answer: SMB and NFS

APFS and Time Machine

• Question: Do I need to change anything in Time Machine to back up an APFS drive?
• Answer: No.

• Question: Do I need to change anything in Time Machine to back up an APFS boot drive?
• Answer: No.

• Question: Can I use AFP to set up Time Machine share points on an APFS drive?
• Answer: No, AFP file sharing won’t work on an APFS drive. Use SMB file sharing instead.