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Bcachefs: Difference between revisions

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m Citation needed. Especially regarding stability compared to ZFS
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→NixOS installation on bcachefs: Cleanup instruction
 
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     --label=hdd.hdd3 /dev/sde \
     --label=hdd.hdd3 /dev/sde \
     --label=ssd.ssd1 /dev/sdf \
     --label=ssd.ssd1 /dev/sdf \
     --label=ssd.ssd2 /dev/sdg
     --label=ssd.ssd2 /dev/sdg \
     --foreground_target=ssd \
     --foreground_target=ssd \
     --promote_target=ssd \
     --promote_target=ssd \
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     --label=hdd.hdd3 /dev/sde \
     --label=hdd.hdd3 /dev/sde \
     --label=ssd.ssd1 /dev/sdf \
     --label=ssd.ssd1 /dev/sdf \
     --label=ssd.ssd2 /dev/sdg
     --label=ssd.ssd2 /dev/sdg \
     --foreground_target=ssd \
     --foreground_target=ssd \
     --promote_target=ssd \
     --promote_target=ssd \
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== Tips and tricks ==
== Tips and tricks ==


=== Generate bcachefs enabled installation media ===
=== Generate bcachefs enabled installation media ===
 
Use following Nix [[Flakes|Flake-expression]] to generate a ISO installation image with a bcachefs enabled kernel
Use following Nix [[Flakes|Flake-expression]] to generate a ISO installation image with a bcachefs enabled kernel
 
{{file|flake.nix|nix|<nowiki>
{{file|flake.nix|nix|<nowiki>
{
{
   description = "Bcachefs enabled installation media";
   description = "Bcachefs enabled installation media";
   inputs.nixos.url = "nixpkgs/nixos-24.11";
   inputs.nixos.url = "nixpkgs/nixos-25.11";
   outputs = { self, nixos }: {
   outputs = { self, nixos }: {
     nixosConfigurations = {
     nixosConfigurations = {
Line 129: Line 131:
           "${nixos}/nixos/modules/installer/cd-dvd/installation-cd-minimal-new-kernel-no-zfs.nix"
           "${nixos}/nixos/modules/installer/cd-dvd/installation-cd-minimal-new-kernel-no-zfs.nix"
           ({ lib, pkgs, ... }: {
           ({ lib, pkgs, ... }: {
             # Might be required as a workaround for bug
             # Required as a workaround for bug
             # https://github.com/NixOS/nixpkgs/issues/32279
             # https://github.com/NixOS/nixpkgs/issues/32279
             environment.systemPackages = [ pkgs.keyutils ];
             environment.systemPackages = [ pkgs.keyutils ];
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The following commands will generate the iso-image which will be available in the directory <code>./result/iso</code>
The following commands will generate the iso-image which will be available in the directory <code>./result/iso</code>
 
<syntaxhighlight lang="console">
<syntaxhighlight lang="console"># nix build .#nixosConfigurations.exampleIso.config.system.build.isoImage
# nix build .#nixosConfigurations.exampleIso.config.system.build.isoImage
</syntaxhighlight>
</syntaxhighlight>


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<syntaxhighlight lang="console">
<syntaxhighlight lang="console">
# nix-shell -p keyutils --run 'keyctl link @u @s'
# keyctl link @u @s
# bcachefs format --encrypted /dev/sda2
# bcachefs format --label=nixos --encrypted /dev/sda2
# bcachefs unlock /dev/sda2
# bcachefs unlock /dev/sda2
</syntaxhighlight>
</syntaxhighlight>


Mount filesystems
Mount filesystems. Use <code>lsblk -o +uuid,fsType | grep bcachefs</code> to get bcachefs partition uuid.
 
There are two ways to mount a bcachefs filesystem. First, by device:


<syntaxhighlight lang="console">
<syntaxhighlight lang="console">
# mount /dev/sda2 /mnt
# mount /dev/disk/by-uuid/<...> /mnt
# mkdir /mnt/boot
# mkdir /mnt/boot
# mount /dev/disk/by-label/boot /mnt/boot
# mount /dev/disk/by-label/boot /mnt/boot
</syntaxhighlight>
</syntaxhighlight>
For better reliability as with any other filesystem, one should mount the filesystem by UUID, by replacing any drive specifiers with it.
When you formatted, there was an external UUID shown, but if you lost it, you can retrieve it using
<syntaxhighlight lang="console">
# lsblk -o +uuid,fsType | grep bcachefs
</syntaxhighlight>
And using it like <code>UUID=<UUID></code> in place of <code>/dev/sda1:/dev/sdb1</code> or even just <code>/dev/sda</code>.
Note: this is currently broken as per this [https://github.com/NixOS/nixpkgs/issues/317901 github issue]. As a workaround, use `/dev/disk/by-uuid/<UUID>` or `/dev/disk/by-id` instead. This seems to work for single device systems atleast, although atleast at the time of this writing I could not get it to work on my 4+ device raid system.


Continue installation as recommended by the [https://nixos.org/manual/nixos/stable/index.html#ch-installation NixOS manual].
Continue installation as recommended by the [https://nixos.org/manual/nixos/stable/index.html#ch-installation NixOS manual].
Before <code>nixos-install</code> you'll have to adapt the generated NixOS configuration to also use the latest Linux kernel supporting Bcachefs. Add the following line to the <code>configuration.nix</code> in your installation root (/mnt):
{{file|/mnt/etc/nixos/configuration.nix|nix|<nowiki>
boot.supportedFilesystems = [ "bcachefs" ];
boot.kernelPackages = pkgs.linuxPackages_latest;
</nowiki>}}


=== Remote encrypted disk unlocking ===
=== Remote encrypted disk unlocking ===
Retrieved from "https://wiki.nixos.org/wiki/Bcachefs"