Despite extensive coverage of much of Big Sur and Apple Silicon, one session was missing from WWDC, that detailing changes in APFS for macOS 11. This article can’t be as authoritative, but I’ll try here to outline some of the improvements which are documented in various sources, including the latest update to the APFS reference documentation.
APFS in macOS 11 changes volume roles substantially. The System volume within a boot Volume Group is now sealed using a tree of cryptographic hashes, as I have detailed here. New roles include:
• Update, used by macOS updates;
• Xart, used by iOS to manage OS access to secure user data;
• Hardware, used for firmware data;
• Backup, used to store Time Machine backups to APFS, as explained below;
• Enterprise, used for storage of enterprise-managed data;
• Prelogin, which lets the system boot to the login screen ready to mount encrypted volumes.
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