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Bcachefs: Difference between revisions

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Note about currently broken bcachefs mounting on NixOS, and add link to github issue.
github issue referenced in wiki is now fixed, so remove note.
 
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[https://bcachefs.org Bcachefs] is a next-generation CoW filesystem that aims to provide features from [[Btrfs]] and [[ZFS]] with a cleaner codebase, more stability, greater speed and a GPL-compatible license. It is built upon Bcache and is mainly developed by Kent Overstreet.  
[https://bcachefs.org Bcachefs] is a next-generation CoW filesystem that aims to provide features from [[Btrfs]] and [[ZFS]] with a cleaner codebase<ref name=":0">citation needed</ref>, more stability<ref name=":0" />, greater speed<ref name=":0" /> and a GPL-compatible license. It is built upon Bcache and is mainly developed by Kent Overstreet.  


== Installation ==
== Installation ==
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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 \
Line 71: Line 71:
     --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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<syntaxhighlight lang="console">
<syntaxhighlight lang="console">
# bcachefs fsck /dev/sda
# bcachefs fsck /dev/sda
</syntaxhighlight>Change partition encryption password for <code>/dev/sda1</code><syntaxhighlight lang="console">
# bcachefs set-passphrase /dev/sda1
</syntaxhighlight>
</syntaxhighlight>


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== Tips and tricks ==
== Tips and tricks ==
=== Generate bcachefs enabled installation media ===
Use following Nix [[Flakes|Flake-expression]] to generate a ISO installation image with a bcachefs enabled kernel
{{file|flake.nix|nix|<nowiki>
{
  description = "Bcachefs enabled installation media";
  inputs.nixos.url = "nixpkgs/nixos-24.05";
  outputs = { self, nixos }: {
    nixosConfigurations = {
      exampleIso = nixos.lib.nixosSystem {
        system = "x86_64-linux";
        modules = [
          "${nixos}/nixos/modules/installer/cd-dvd/installation-cd-minimal-new-kernel-no-zfs.nix"
          ({ lib, pkgs, ... }: {
            # Might be required as a workaround for bug
            # https://github.com/NixOS/nixpkgs/issues/32279
            environment.systemPackages = [ pkgs.keyutils ];
            boot.supportedFilesystems = [ "bcachefs" ];
          })
        ];
      };
    };
  };
}
</nowiki>}}
The following commands will generate the iso-image which will be available in the directory <code>./result/iso</code>
<syntaxhighlight lang="console">
# git init
# git add flake.nix
# nix build .#nixosConfigurations.exampleIso.config.system.build.isoImage
</syntaxhighlight>


=== NixOS installation on bcachefs ===
=== NixOS installation on bcachefs ===
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<syntaxhighlight lang="console">
<syntaxhighlight lang="console">
# mkfs.fat -F 32 -n boot /dev/sda1
# mkfs.fat -F 32 -n boot /dev/sda1
# nix shell -p bcachefs-tools
# mkfs.bcachefs -L nixos /dev/sda2
# mkfs.bcachefs -L nixos /dev/sda2
</syntaxhighlight>
</syntaxhighlight>


In case you want to enable filesystem encryption, there's a workaround for [https://github.com/NixOS/nixpkgs/issues/32279 a bug] affecting NixOS 23.11. Formatting and unlocking the encrypted partition would look like this
Formatting and unlocking the encrypted partition would look like this


<syntaxhighlight lang="console">
<syntaxhighlight lang="console">
# nix-env -iA nixos.keyutils
# nix-shell -p keyutils --run 'keyctl link @u @s'
# keyctl link @u @s
# nix-shell -p bcachefs-tools
# bcachefs format --encrypted /dev/sda2
# bcachefs format --encrypted /dev/sda2
# bcachefs unlock /dev/sda2
# bcachefs unlock /dev/sda2
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</syntaxhighlight>
</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>.
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/<UUID1>:/dev/disk/by-uuid/<UUID2>` instead.


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 ===
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   after = [ "local-fs.target" ];
   after = [ "local-fs.target" ];
   wantedBy = [ "multi-user.target" ];
   wantedBy = [ "multi-user.target" ];
  environment = {
    DEVICE_PATH = "/dev/sda1";
    MOUNT_POINT = "/mnt";
  };
   script = ''
   script = ''
     #!${pkgs.runtimeShell} -e
     #!${pkgs.runtimeShell} -e
     ${pkgs.keyutils}/bin/keyctl link @u @s
     ${pkgs.keyutils}/bin/keyctl link @u @s
     while [ ! -b /dev/sda1 ]; do
 
       echo "Waiting for /dev/sda1 to become available..."
    # Check if the device path exists
     if [ ! -b "$DEVICE_PATH" ]; then
      echo "Error: Device path $DEVICE_PATH does not exist."
      exit 1
    fi
 
    # Check if the drive is already mounted
    if ${pkgs.util-linux}/bin/mountpoint -q "$MOUNT_POINT"; then
      echo "Drive already mounted at $MOUNT_POINT. Skipping..."
      exit 0
    fi
 
    # Wait for the device to become available
    while [ ! -b "$DEVICE_PATH" ]; do
       echo "Waiting for $DEVICE_PATH to become available..."
       sleep 5
       sleep 5
     done
     done
     ${pkgs.bcachefs-tools}/bin/bcachefs mount -f /etc/keyfile_test /dev/sda1 /mnt
 
    # Mount the device
     ${pkgs.bcachefs-tools}/bin/bcachefs mount -f /etc/keyfile_test "$DEVICE_PATH" "$MOUNT_POINT"
   '';
   '';
   serviceConfig = {
   serviceConfig = {
Retrieved from "https://wiki.nixos.org/wiki/Bcachefs"