Detailed account of disk, volume and folder layouts on Big Sur’s boot disks, complete with roadmaps which are downloadable as PDFs.
Volume Group
Boot disk volume layout is intricate in Big Sur. M1 Macs lose the EFI partition on their internal SSDs and gain two more for APFS. Contents of /System/Volumes has also changed.
Diagrams of the layout of volumes on boot disks for macOS 10.13 to 11, covering both Intel and M1 models.
Volume layouts are fairly straightforward until you have two or more bootable systems with Volume Groups. Details and advice for those with macOS 10.15 or 11.
A complete guide to the structure and layout of APFS startup disks from High Sierra to Big Sur (Intel), together with tear-out PDF charts.
Provision of maintenance procedures and tools is at the heart of software engineering, but not in macOS.
If something goes wrong with Catalina’s boot Volume Group, it seems there’s no way to repair it, or change the Data volume. Or is there?
Older versions of Catalina can fail to erase the System and Data volumes, but 10.15.6 should be able to, making clean re-installation simpler.
From SIP to a protected read-only System volume, macOS 11 takes system protection a big step further with cryptographic verification.
macOS Catalina is the first version of macOS which boots not from a single volume, but from two: […]
