For those with more than one Mac on the local network, use the Caching Server on those machines. 1. Internet Recovery will boot from the Caching Server (if a macos install is cached) 2. Nuke and pave
2. Restore user data from regular backup It’s actually a really fast method if the user data is on an external disk. I regularly use the Time Machine service in a Truenas Scale NAS, although slower it hasn’t failed me the last 5 years its been used. https://support.apple.com/en-us/102860
Wrinkle? I think it’s proving the point you set out to refute.
It's either a wrinkle or a show-stopperr, depending on your use case, I agree that on Apple Silicon Macs you're dead in the water if your internal SSD fails. The next question is: what's the likelihood of that happening in the real world compared to HDD failure?
It would be very interesting to see what SSD failure rates are on today's Macs, compared to HDD failure rates.
The question of risk analysis comes in here. If you're worried about the downtime incurred with a failed SSD, have you considered how to deal with other component failures on the motherboard such as memory or CPU that render the Mac unusable? At some point, depending on that risk analysis, a spare Mac becomes part of the equation.
In the more likely use cases of protecting against a corrupted file system, overcoming an under-sized internal disk, or as a safety net for installation of a system update, the ability to run from an external SSD drive is still available and is an option for those use cases- even on Apple Silicon.
I’m not thrilled to hear this but in the end it probably won’t affect me. I prefer to have a bootable external copy of MacOS as an emergency backup incase of a hard drive failure but the solid state drives they use are quite reliable and I can’t think of the last time I’ve had one fail or even heard of one failing.
If you have your hard drive encrypted what’s the security advantage of preventing an external boot drive?
What about macOS getting corrupted and unable to boot? It is not about drive reliability, it is more about software suddenly failing and your Mac unable to boot. The external drive was always a lifesaver for booting your Mac and being able to recover anything from the internal drive that might not have been backed up yet. But Apple figures that people can hopefully boot to recovery mode and reinstall macOS. More challenging with a managed Mac in Enterprise and a macOS update fails and renders a Mac unable to boot.
To answer your question, if you have the drive encrypted with FileVault 2 and you boot from an external disk, the internal drive will prompt for the Mac password to unlock the disk. Also, starting with the T2 security chip in Macs, you have to boot into Recovery Mode and change the security settings to allow the Mac to boot from an external disk. It is disabled by default.
Out of curiosity, when was the last time you heard of macOS getting corrupted on a system version released since Apple started locking down the OS?
Back in December I had a conference call with Apple about the reliability and functionality of ASR on macOS and regarding Apple Silicon Macs in particular. They indicated that they were working to resolve the ASR/Apple Fabric issue, but they made it very clear that copying macOS system files was not something that would be supportable in the future. Many of us in the Mac community could see that this was the direction Apple was moving, and now we finally have confirmation. Especially since the introduction of APFS, Apple has been moving towards a lockdown of macOS system files, sacrificing some convenience for increased security.
An interesting update from Mike Bombich which adds more context to why Apple moved away from use of ASR to copy the operating system for a bootable backup.
My feeling after reading what Mike has written is that this "bug" may not be considered a "bug" by Apple.
Thank you PERockwell and PDXGuy1959 for clarifying the issue and the solution options.
To summarize:
a. Intel Macs appear to be able to use the usual tools (SuperDuper/CarbonCopyCloner) to make bootable backups still.
b. For Apple Silicon Macs, the method has changed per Mike Bombich's article -- do a clone of the data-only volume, then install macOS to add a system to it.
A bit more work, but a more secure backup is the result.
Comments
1. Internet Recovery will boot from the Caching Server (if a macos install is cached)
2. Nuke and pave
It’s actually a really fast method if the user data is on an external disk. I regularly use the Time Machine service in a Truenas Scale NAS, although slower it hasn’t failed me the last 5 years its been used.
https://support.apple.com/en-us/102860
It would be very interesting to see what SSD failure rates are on today's Macs, compared to HDD failure rates.
The question of risk analysis comes in here. If you're worried about the downtime incurred with a failed SSD, have you considered how to deal with other component failures on the motherboard such as memory or CPU that render the Mac unusable? At some point, depending on that risk analysis, a spare Mac becomes part of the equation.
In the more likely use cases of protecting against a corrupted file system, overcoming an under-sized internal disk, or as a safety net for installation of a system update, the ability to run from an external SSD drive is still available and is an option for those use cases- even on Apple Silicon.
An interesting update from Mike Bombich which adds more context to why Apple moved away from use of ASR to copy the operating system for a bootable backup.
My feeling after reading what Mike has written is that this "bug" may not be considered a "bug" by Apple.