I’d say that the most important takeover of this approach is to stop all the containers before the backup. Some applications (like databases) are extremely sensitive to data corruption. If you simply ´cp´ while they are running you may copy files of the same program at different point in time and get a corrupted backup. It is also important mentioning that a backup is good only if you verify that you can restore it. There are so many issues you can discover the first time you recover a backup, you want to be sure you discover them when you still have the original data.

The decryption key is more than 20 random character, so if you get only half of it is not a biggie and it doesn’t look like anything interesting.

It is on the internet mostly because I don’t have anything else to host it locally. But I see some benefit: I wanted for the server to be available immediately after a power failure. If it fetches the key from internet I just need for the router to be online, if it fetches it from the local network I need another server running unencrypted disk.

Linux from chromebook is just a configuration you enable from the settings menu. If offers you a shell which is similar to a Ubuntu and you can install standard Linux software using the “apt install” command. Said so, if they cannot even install chrome extensions this is likely disabled too.

Second reason. It may run your vpn, with the server down you cannot connect to it and provide the decryption key unless you are connected to the same network.

There are some good answer around where the server can easily decrypt automatically as long as it is connected in your home but will likely fail at a thief’s home. These are a much safer setup than keeping data unencrypted even if they are not bullet proof.

The issue I see with TPM is that it will always unlock the drive as long as it is connected to the same motherboard. It means you have to trust all the services you run to be correctly secured. Like there is little reason to encrypt your hard drive in this way if later you have a samba share open without any password.

I’ve configured something similar. The /boot partition is the only unencrypted. In the initramfs there is a script that downloads half of the decryption key from http, while the other half is stored in the script itself. The script implements automated retry until it can fetch the key and decrypt the root partition.

My attack model here is that, as soon as I realize someone stole my NAS I can shutdown the server hosting half of the decryption key making my data safe. There is a window where the attacker could connect it to a network and decrypt the data, but it is made more difficult by the static network configuration: they should have a default gateway with the same IP address of mine.

On my TODO list I also have to implement some sort of notification to get an alert when the decryption key is fetched from internet.

Terramaster is just a PC in a NAS form factor. You can install your favourite OS without any issue