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.
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.
They also says that installing a different os will invalidate the warranty. But their x86 models (I wasn't aware of the arm) literally ship with a USB drive connected to an internal USB port which starts the setup of their custom Linux if it detects no OS on the internal drives. You just swap that pendrive and you install whatever you want. I cannot say it works for all the models, but I did a little research before buying mine and I can say it run debian for more that one year without any compatibility issue.
I agree, but having a webui is nicer on android, so I installed https://www.filestash.app/ configured to use samba as backend so permissions and passwords are the same
I don't have a testing environment, but essentially all my services are on docker saving their data in a directory mounted on the local filesystem. The dockerfile reads the sha version of the image from an env file. I have a shell script which:
if a new Docker version is broken rolling back is as simple as copying the old version in the env file and recreating the container. If data gets corrupted I can just copy the last working status from an old snaphot.
The whole os is on a btrfs volume which is snapshotted regularly, so ideally if an update fucks it up beyond recovery I can always boot from a rescue image and restore an old snapshot. But I honestly feel this is extra precaution: in years that I run debian on all my computers, it never reached the point of being not bootable.
there is a feature request with a lot of good comments on their forum. The summary of the last time I checked it was on the lines: "it is a reasonable request but it is terribly hard to implement it correctly and since we currently have no capacity to do it we prefer leaving it not implemented instead of offering any alternative which could give a false sense of security"
Good point, I'll add it on my TODO list