Bcachefs: Difference between revisions

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@@ Line 57: / Line 57: @@
      --label=hdd.hdd3 /dev/sde \
      --label=ssd.ssd1 /dev/sdf \
-     --label=ssd.ssd2 /dev/sdg
+     --label=ssd.ssd2 /dev/sdg \
      --foreground_target=ssd \
      --promote_target=ssd \
@@ Line 71: / Line 71: @@
      --label=hdd.hdd3 /dev/sde \
      --label=ssd.ssd1 /dev/sdf \
-     --label=ssd.ssd2 /dev/sdg
+     --label=ssd.ssd2 /dev/sdg \
      --foreground_target=ssd \
      --promote_target=ssd \
@@ Line 113: / Line 113: @@
 == 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-25.11";
+  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, ... }: {
+            # 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"># nix build .#nixosConfigurations.exampleIso.config.system.build.isoImage
+</syntaxhighlight>
 === NixOS installation on bcachefs ===
@@ Line 133: / Line 167: @@
 <syntaxhighlight lang="console">
 # mkfs.fat -F 32 -n boot /dev/sda1
-# nix shell -p bcachefs-tools
 # mkfs.bcachefs -L nixos /dev/sda2
 </syntaxhighlight>
@@ Line 140: / Line 173: @@
 <syntaxhighlight lang="console">
-# nix-shell -p keyutils --run 'keyctl link @u @s'
+# keyctl link @u @s
-# nix-shell -p bcachefs-tools
+# bcachefs format --label=nixos --encrypted /dev/sda2
-# bcachefs format --encrypted /dev/sda2
 # bcachefs unlock /dev/sda2
 </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">
-# mount /dev/sda2 /mnt
+# mount /dev/disk/by-uuid/<...> /mnt
 # mkdir /mnt/boot
 # mount /dev/disk/by-label/boot /mnt/boot
 </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].