Debian BTRFS install

Question

Partition disks:

Shell:

https://www.reddit.com/r/debian/comments/aa3zta/install_debian_to_a_btrfs_subvolume_and_not_the/eczobqb/

Once the partitioning step is complete, select "Back" in the debian installer to return to the list of steps the installer is working through and break out to a shell by choosing the option "Execute a shell".

The author said /target was there when I finished editing the partition and entered the shell via return. However, I tried several times and /target was only created after the Debian install started. So I couldn't proceed as the author explained.

https://www.youtube.com/watch?v=wtMj8KPRlws

YouTube also explains something similar in video. However, if I enter the shell before the Debian installation proceeds as shown in this video, /target is not created. My Debian installer only creates /target after the Debian installation has started.

I know there is also a way to create subvolumes after installing Debian on the main volume without this process. However, In the current version of Debian, there was no up-to-date manual showing successful results simply by following the command line. I wanted to copy, but I failed because the result was different.

I want to install Debian on a subvolume.

Answer 1

With Debian 11 (I didn't check prior versions) everything is much easier. You just have to use the live CD to perform the installation using the graphic calamares installer. The @ and @home btrfs subvolumes will be created automatically and mounted properly.

1. Fire up the live CD and, in the Activities overview, click the installer icon. Follow the defaults until you get to the partitions screen.
2. Choose manual partitioning. Create a new partition ~256MB with filesystem FAT32, the boot flag on, and mount point /boot/efi
3. Also make a swap partition with the size you deem appropriate.
4. Allocate the space left to a btrfs partition with mount point /.

Finish the installation process as usual and

That's it!

Answer 2

Choose Expert mode (under advanced options) instead of Graphical install. Unlike in Graphical install, the installation of the system does not start automatically after partitioning and writing the changes to disk.

The moment you will need to switch to shell is just after partitioning and writing changes to disk and before launching the system installation to disk. /target will be there. You can switch to shell by Ctrl+Alt+F1, create subvolume and make it as target for the installer.

For creating the subvolume, I used steps described here: https://www.reddit.com/r/debian/comments/7fyeia/is_there_a_way_to_install_debian_to_a_btrfs/dqg3h6l/

Answer 3

The Debian-Installer does not yet support creating subvolumes, see Bug #686097. It must first finish creating the partition(s) and will then mount the future root partition under /target. Now you can switch to the shell, create the subvolume and rearrange the mountpoints.