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persistence guide

Since version 0.2, heads allows for USB persistence using tomb. The process uses some automagic to figure out where to place it.

setup

The setup is pretty straightforward. Issue sudo heads-persistent-setup in a terminal window and you will be guided through the process. Pay attention to the text that shows to get a good understanding.

The script will look for free space on the USB drive you are using to boot heads and will create an ext2 partition out of it. Further on, it will mount that partition and try to create a tomb, along with its key. You will be prompted for the tomb size you would like. If that goes well, you have to choose a passphrase for the tomb key...

A tomb will be dug, formatted and locked with the key that was created. Currently, the key resides at the same place where the tomb is, but in the future, as the script develops, it will not be mandatory.

When done, the tomb will be opened and mounted. You will get a short explanation in the terminal. You can close the tomb by issuing sudo tomb close persistence.

usage

When you finish the setup for the first time, the persistence tomb stays open on the system and you can use it immediately. If you reboot or close the tomb, you can now initialize persistence by issuing sudo heads-persistent-load. This script will look for the before created partition, try to mount it, and then try to open the persistence tomb. If you set up bind hooks (see tips below), this is the time when directories get overlayed.

tips

A simple tomb as such might not be super-useful for everyone. Luckily tomb has some nifty features. One of them is called bind-hooks. A bind hook executes when a tomb is open, and binds a directory inside the tomb to a directory on the filesystem. This way you can override parts of the system you want to be persistent. When you were setting up persistence, this was mentioned, and an example bind hook was dropped inside the tomb, called bind-hooks.example.

The syntax of the bind-hooks file is the following:

dir/relative/to/tomb	dir/relative/to/users/home

So, for example, it can be very useful to have a gnupg directory with your keys inside the tomb, and bind it to the system when you open the tomb.

gnupg-keys	.gnupg