Big Sur Time Machine Migration

Howard Oakley reports a smooth experience upgrading to macOS 11.0.1 Big Sur. Good news, but I’m waiting for the 11.1 update while preparing for the Big Sur big move by getting my Time Machine updates in order: I retired the old Time Capsule, removed the hard disk and repurposed it as a local Time Machine backup disk. Goodbye NAS Time Machine backups.

As Oakley pointed out just after WWDC20, and as Ars Technica confirms in their Big Sur review, updating to Big Sur comes down to 2 Time Machine choices: 1) the legacy HFS+ hard link way and, 2) The APFS snapshot way. There is no way to migrate from HFS+ Time Machine to APFS Time Machine except by starting afresh. The default Big Sur Time Machine setting formats a new disk as APFS as shown in the video. Goodbye HFS+ Time Machine backups.

Oakley’s key advice is this:

I also strongly recommend that, whether using HFS+ or APFS to store your Time Machine backups in future, you start making a fresh backup set with Big Sur. You’ll have to do that if you switch to using APFS anyway, but following the problems which occurred with Catalina, you’ll be much better off if you archive your old backup set and start afresh.

To do that I plan to:

  1. Backup macOS Catalina 10.15.7 to 2 different Time Machine hard disks
  2. Turn off automatic Time Machine backups
  3. Upgrade to macOS Big Sur 11.1, then if the upgrade is successful…
  4. Wipe one of the Catalina Time Machine hard disks and let Big Sur Time Machine create a new APFS backup with auto backups.

I’ll let you know how it goes.