(In fact, Big Sur doesn’t even read files directly from this System volume to boot your Mac. With Big Sur, however, Apple went a step further, adding strong cryptographic protections when storing system content on what is now called a Signed System Volume.
Eventually, all the leading apps figured out how to do this: see “ Carbon Copy Cloner 5.1.10” (26 August 2019), “ ChronoSync 4.9.5 and ChronoAgent 1.9.3” (11 October 2019), and “ SuperDuper 3.3” (30 November 2019). Now a bootable duplicate had to have a System and a Data volume, and they had to be combined correctly into an APFS volume group. This architectural change forced backup apps that make bootable duplicates to jump through hoops, since they couldn’t just read and write data anymore.
The System volume is also read-only, so malicious software cannot modify the operating system, whereas the Data volume that contains your files remains read-write so you can install apps and create and modify documents. The two volumes appear as a single entity in the Finder and wherever you might select or navigate files. A System volume holds all the files macOS needs to operate, while the Data volume contains only your data.
In 10.15 Catalina, Apple introduced APFS volume groups, a way of bundling separate volumes together to create a bootable macOS. Why Bootable Duplicates Have Become Difficult to Make And once we’ve done that, we can reassess the role of a bootable duplicate in a modern backup strategy. To understand why this seemingly simple task-just read all the data from one drive and write it to another-is causing such consternation, we need to step back briefly.
That’s the complexity of creating a bootable duplicate of your startup volume, also known as a clone. However, there is one general concern that has caused us to hesitate to recommend upgrading. Is it time to upgrade to macOS 11 Big Sur? I’ll write more about that soon. The Role of Bootable Duplicates in a Modern Backup Strategy #1621: Apple Q3 2022 financials, Slack's new free plan restrictions, which OS features do you use?.#1622: OS feature survey results, Continuity Camera webcam preview, OWC miniStack STX.#1623: How to turn off YouTube's PiP, use AirPlay to Mac, and securely erase Mac drives.#1624: Important OS security updates, rescuing QuickTake 150 photos, AirTag alerts while traveling.#1625: "Far Out" event on September 17th, iPadOS 16 delayed, FileMaker's future, free NMUG membership, using Note tags and Quick Note.