My Linux System Setup

Everything should be as simple as possible. I want to be able to keep it all in my head.

Current System

My system currently has the following disks.

Disk	Type	Size	Speed	Linux Device Name
Disk A	SSD	932 GB	Fast	/dev/nvme0n1
Disk B	SSD	1863 GB	Fast	/dev/nvme1n1
Disk C	HDD	932 GB	Slow	/dev/sda

Note that if you buy a 1 TB disk you will get a disk with $1000 * 1000^3$ bytes. But we count in multiples of 1024. Which means that the actual size is equal to $932 * 1024^3$ or 932 bytes.

These disks are currently partitioned the following way.

Disk	Part	Size	Label	File system
Disk A	1	2 GB	Boot	vfat
Disk A	2	16 MB	?	?
Disk A	3	930 GB	Windows	NTFS
Disk B	1	1863 GB	Linux	btrfs + LUKS
Disk C	1	932 GB	Backup	btrfs + LUKS

This encrypted Linux partition on "Disk B" has a number of btrfs subvolumes.

• /tree - Actual important data (currently 87 GB)
• /data - Media and Downloads (currently 616 GB)
• /root - Linux Root partitions (currently 35 GB)
• /snap - BTRFS Snapshots of /tree

Putting my Linux root on a btrfs volume allows me to create as many roots as I want. However, in practice this was not very beneficial.

Possible Future System

I am considering to go to the following layout. The goal is to simplify the system as much as possible. Configuring an encrypted btrfs as a Linux root is not trivial. While I managed to configure it and have a running system, it is not simple and has multiple points of failure.

Disk	Part	Size	Label	File system
Disk A	1	2 GB	Boot	vfat
	2	16 MB	?	?
	3	930 GB	Windows	NTFS
Disk B	1	400 GB	Root 1	ext4
	2	400 GB	Root 2	ext4
	3	663 GB	Data	ext4
	4	400 GB	Tree	btrfs + LUKS
Disk C	1	1000 GB	Backup	ext4

Maybe the naming of my tree and data partitions could be improved. Not sure yet however.

• Rename /tree to /data
• Rename /data to /media

Migration To the future system

• Create a backup of /data/tree to the external HDD
• Partition Disk C like this:

Disk	Part	Size	Label	File system
Disk C	1	200 GB	HDD Root	ext4
	2	730 GB	HDD Data	btrfs + LUKS

• Move /data and /tree to HDD (btrfs send)
• Create a bootable system on Disk C
• Boot to "HDD Root"
• Partition Disk B
• Setup Root 1
• Configure auto mount for /tree and /data

The Data Partition

I always try to keep my files separate from files that are not mine and generated. I don't care about preserving files I did not create.

As far as I know there are 3 types of data on my computer.

• /root - Operating system data. Everything needed to boot a Linux or Windows system. There is no need to preserve these files. Re-installing a Linux system is not difficult and something I do regularly.
• /tree - Important personal files, everything from projects, notes, to photos. This is the only directory I actually care about. It should be backed up regularly. The current size is around 90 GB.
• /data - Media files, movies, music, other stuff. I did not make these files, and they can be found again. I don't care if I loose it.

I encrypt the /tree partition to keep the integrity of these files. I don't want random windows programs modifying or reading this data. If I want full system security I would have to encrypt everything and sign the boot image.

Backup

Recovering from a backup should be as simple as possible.

If everything dies on me, I can:

1. boot from a USB with arch, And reinstall a root file-system
2. Extract the latest backup into the /tree partition

To recover everything I can boot from a USB and extract everything into a new file system. To recover a single file I can extract a given sub folder or file using tar.

I would like these backup files to live on a simple unencrypted file system. This allows me to rescue some backup files when something gets corrupted on this backup disk. A backup should be a single file that always contains all the data, and not require any other files. I don't want multiple backups to share data on the disk. The multiple copies allow for some data corruption to be recovered. The encryption should be self contained per file, and not require an external key.

To perform a backup I create a zstd compressed tar archive encrypted with age using my long root password. These files are tagged by their date tree-yyyy-mm-dd.tar.zst.age. I choose zstd for its compression speed.

I am not using GPG because I would need to store the key somewhere. So all I need is simple symmetric encryption with a good passphrase. The salt should be stored in the file itself, so they are completely independent.

To perform the backup run the following:

tar -c --zstd /tree | age -e -p  -o "tree-$(date +'%F').tar.zst.age"

Recover data:

age -d "tree-yyyy-mm-dd.tar.zst.age" | tar -x --zstd

Dual Root

I split my system into two symmetric root partitions. This allows me to install the other root partition from the current one and then switch. After a switch I can still access the files from the previous partition and copy them over. This allows me to completely reinstall the system with little effort. My goal is to achieve something similar as docker or vm images, but fast, simple and on bare metal. The system configuration should be stored in /tree as bash scripts or direct configuration files. This configuration can be applied on a lean root partition.

An alternative method could be to have a single big root partition and a smaller "Recovery" partition. This wastes less space, but I cannot easily reinstall a system, as I might lose data that was not correctly stored in /data. If something went wrong, I am stuck with the recovery system. This is why I greatly prefer the symmetric system.

Windows

The only reason I have windows installed is so that I can play some demanding games. Most small games work fine on Linux, but more demanding games require Windows to perform well. This does not mean that Windows is better or faster, not at all. This means that these games are created, and optimized for Windows. I don't want to deal with any issues when playing games, so I just directly boot Windows when needed. Dual booting also allows me to keep "gaming" and "working on hobby projects" separate.

Dual booting Windows is not difficult at all with systemd-bootd. This bootloader automatically detects the Windows boot image and adds it to the menu.

A VM with GPU pass-through might be an option some day.

Installing Linux

My preferred distribution is currently Arch Linux. The simplicity of the distribution allows me to understand the entire system.

The very first time installing Arch requires creating a installation USB. Download the image and write it directly to the USB.

Subsequent installations can be done directly from arch, due to the two root system we apply.

• https://wiki.archlinux.org/title/installation_guide
• https://wiki.archlinux.org/title/User:Altercation/Bullet_Proof_Arch_Install

Installation steps (simplified)

# Create the filesystem
mkfs.ext4 /dev/ROOT2
mount /dev/ROOT2 /mnt

# Mount
mount -m /dev/BOOT /mnt/boot

# Install the base archilniux filesystem
pacstrap -K /mnt base linux linux-firmware

# Set the root password
arch-chroot /mnt
passwd

> /etc/fstab
echo '/dev/nvme0n1p1 /boot vfat rw,noatime,iocharset=ascii,utf8	0 2' >> /etc/fstab
# TODO -> mount /data

Install everything else

arch-chroot /mnt

ln -s /usr/share/zoneinfo/Europe/Amsterdam /etc/localtime
hwclock --systohc

> /etc/locale.gen
echo 'en_US.UTF-8 UTF-8' >> /etc/locale.gen
echo 'nl_NL.UTF-8 UTF-8' >> /etc/locale.gen
locale-gen

echo 'LANG=nl_NL.UTF-8' >> /etc/locale.conf
echo 'LC_MESSAGES=en_US.UTF-8' >> /etc/locale.conf
echo 'pctom' > /etc/hostname

Bootloader

bootctl install

/boot/loader/loader.conf

default arch.conf
timeout 2
console-mode keep

/boot/loader/entries/arch.conf

title   Arch Linux
linux   /vmlinuz-linux
initrd  /amd-ucode.img
initrd  /initramfs-linux.img
options root="LABEL=ARCH_ROOT" rw

Enable Network

/etc/systemd/network/10-ether.network

[Match]
Type=ether

[Network]
DHCP=yes

systemctl enable --now systemd-resolved systemd-networkd

pacman -Syy

Extras

Starting a QEMU emulator

The ovmf bios makes QEMU boot with uefi.

pacman -S qemu-img qemu-system-x86_64 edk2-ovmf
qemu-img create -f qcow2 root.qcow2 8G
qemu-system-x86_64 --enable-kvm --cpu host -bios /usr/share/ovmf/x64/OVMF.fd -boot d -m 2G -cdrom ./archlinux-2023.05.03-x86_64.iso -hda root0.qcow2 -display gtk -vga virtio

Encrypted btrfs root

I played around with a LUKS encrypted btrfs root.

Android

How do I sync my phone with my /tree? What do I want to sync? Only Photos?