How to reserve Time Machine space on an APFS drive

In macOS Big Sur, you can finally use APFS-formatted volumes as Time Machine destinations. They aren’t backwards compatible with macOS Catalina or earlier versions of macOS, and they require erasing an existing HFS+ (Mac OS Extended) disk to reformat—you can’t convert HFS+ to APFS for Time Machine and retain the drive’s data in place as you can when upgrading your macOS startup volume to High Sierra (SSDs), Mojave (Fusion Drives, HDDs), or later. (See “macOS Big Sur supports Time Machine on APFS-formatted drives, but there are a few catches,” for more details.)To read this article in full, please click here