JamesBrickley

There is more to it than just having a servo press or press-hold the power button.  You need to have some sort of KVM connected to HDMI or USB-C Display and KB/mouse and route the video to remote control of some sort.  The SSD's are factory encrypted and turning on FileVault only generates a public/private key, stuffs the private key into the Secure Enclave and uses the public key to generate the FileVault Recovery Key which gives you a way to reset the password if forgotten.  If a M1 / M2 Mac Mini is rebooted in the data center, it comes up to a pre-boot authentication screen and it's not online with the network.  When you enter your ID/PW it then boots macOS and single-signs onto the desktop. If the passwords are out of sync it will have a second real login screen.  The pre-boot authentication screen is skinned to look like the real login screen but it most certainly is not.  Using Pi-KVM you can attach to HDMI & KB/Mouse and the Pi-KVM is networked so you can load it's web page, login and manually login to the Mac Mini.  The servo solution is to physically press the power button.  Using a Pi-KVM with a server you could mount the Pi-KVM internally with a PCI slot cover passing cables in and out of a racked server.  Internally you can reach the power pins on the server motherboard.  Pi-KVM is useful when your server / PC / Mac doesn't have enterprise class BMC which allows for IPMI, iDRAC, iLO found on real servers.  The old Apple Xserves had iLO Lights-Out management.  But none of the modern Macs have the necessary BMC chips and remote management functionality of PC servers.  It would be nice to have that.  Companies like MacStadium are no-doubt developing internal solutions to solve the problem.  

Good luck actually sourcing RaspberryPi hardware there are severe shortages globally.  Seems some commercial vendors are buying up all the rPI's and they are being given priority by the manufacturer.

Here is a good explainer of how updates have changed in macOS and what is happening:
https://eclecticlight.co/2022/03/19/explainer-macos-updaters/

Howard Oakley has a lot of information on his blog posts and quite a few extremely useful MacAdmin tools. 

You really cannot compare Linux / FreeBSD / Windows to macOS in regards to OS updates, it's radically different and goes well beyond simply updating files. Apple's security and chain of trust changes are considerable.

$49.99 for a plastic tray with silicon pads? I'm in the wrong business...

neilm said:

So unless Apple has re-engineered Time Machine, they presumably must have updated APFS to support hard links. Anyone know?

It appears to be using APFS snapshots instead.  At least on an APFS time machine drive.  Apple only keeps local snapshots for 24 hours so if you wait too long between backups it will likely not have the associated snapshot to delta copy to the Time Machine.  But with APFS and snapshots and the improvements made to Time Machine it is still faster on APFS even if it needs to recopy a large 10GB modified file and overwrite the backup instead of only copying a delta of the two snapshots. If they allow more than 24 hours of snapshots it will consume considerable disk space and even on Linux / FreeBSD systems using ZFS knowledgeable users complain about their disk space disappearing.  Despite those folks should be smart enough to manually manage their snapshots or automate it better with cron jobs.  So I can understand why Apple would place such a snapshot limit to avoid user confusion.  They do things like that all the time instead of providing in-depth technical views and attempt to make it easy; they just arbitrarily set a default configuration and leave it at that.

rob53 said:

What about formatting external RAID HDD as APFS? OWC’s SoftRaid is waiting for Big Sur to make this happen. My RAID can’t be used to backup my Catalina APFS volumes. 

You do not need to format your NAS as APFS.  But you need to setup something to act like an Apple Time Capsule. For example, my ZFS NAS has a tiny virtual machine running Linux that simulates the Apple Time Capsule.  When I create a backup using the Apple Time Capsule it creates a DMG sparse image for each Mac.  When doing so from a Big Sur Beta test Mac it creates the DMG sparse disk using AFPS.  If I encrypt that image it still works.  This is how off-the-shelf NAS providers like Synology work. They run the open source tools to simulate a Time Capsule over SMB (Netatalk). 

You can do this without a Time Capsule emulation but it's a bit harder and requires you enable Time Machine over SMB on each Mac which is officially unsupported.  It does in fact work.  Here is the override.  But I don't recommend this method.

defaults write com.apple.systempreferences TMShowUnsupportedNetworkVolumes 1

The supported method is if you were to run say a Mac mini with macOS High Sierra or above you could do it that way.  Just mount the NAS storage on the Mac mini  and turn on File Sharing select the mounted NAS folder and right-click it select Advanced Options and check the box to enable Time Machine network location.  It will provide the intermediate Time Capsule like functionality and it will be fully supported by Apple.  You don't even need macOS Server.  It's quite a bit overkill in overhead and cost considering you can do the same with even an old Raspberry Pi and Netatalk open source project for far less and with far less overhead. Heck you could run quite a bit more on a Raspberry Pi 3+ and not even stress it much.  Like a print server and a Pi-Hole (network wide ad-blocker), etc.  But you could probably find alternative uses for the Mac mini to do many more things as well.

Remember that Mac's are still UNIX and they play extremely well with UNIX/Linux and when there is a will there is a way.  You don't need to do everything with Apple. But Apple still makes things rather easy, you just need to know how to peel back the layers to find it at times.  Bet most people didn't know that macOS High Sierra can run a Time Machine server.   I just checked it's still an option.