Move from ZFS to btrfs

hosts/nixos-testbed/configuration.nix

@@ -7,11 +7,11 @@
 
   sydnix = {
     impermanence = {
-      enable = true;
+      enable = false;
       directories = [
-        # Warning: Neither /var/lib/nixos nor any of its parents are persisted.
+        # "Warning: Neither /var/lib/nixos nor any of its parents are persisted.
         # This means all users/groups without specified uids/gids will have them
-        # reassigned on reboot.
+        # reassigned on reboot."
         "/var/lib/nixos"
         "/etc/ssh"
       ];
@@ -30,11 +30,11 @@
       enable = true;
       systemd.enable = true;
 
-      systemd.initrdBin = with pkgs; [
-        zfs
-        coreutils
-        babashka
-      ];
+      # systemd.initrdBin = with pkgs; [
+      #   zfs
+      #   coreutils
+      #   babashka
+      # ];
     };
 
     loader = {

hosts/nixos-testbed/disko-config.nix

@@ -1,18 +1,18 @@
-# sudo nix --experimental-features "nix-command flakes" run github:nix-community/disko/latest -- --mode disko /nixos/hosts/nixos-testbed/disko-config.nix
-# time sudo nixos-install --flake /nixos#nixos-testbed
+# sudo nix --experimental-features "nix-command flakes" run github:nix-community/disko/latest -- --mode disko /persist/dots/hosts/nixos-testbed/disko-config.nix
+# time sudo nixos-install --flake /persist/dots#nixos-testbed
 { lib, ... }:
 {
   # imports = [ disko.nixosModules.disko ];
-  boot.zfs.extraPools = [ "rpool" ];
-  boot.zfs.devNodes = "/dev/disk/by-path";
-  boot.initrd.supportedFilesystems = [ "zfs" ];
-  boot.supportedFilesystems = [ "zfs" ];
+  boot.initrd.supportedFilesystems.btrfs = true;
+  boot.supportedFilesystems.btrfs = true;
+
+  fileSystems."/persist".neededForBoot = true;
 
   disko.devices = {
     disk = {
-      broot = {
+      bootroot = {
         type = "disk";
-        device = "/dev/vda";
+        device = "/dev/sda";
         content = {
           type = "gpt";
           partitions = {
@@ -29,63 +29,42 @@
             root = {
               size = "100%";
               content = {
-                type = "zfs";
-                pool = "rpool";
+                type = "btrfs";
+
+                mountpoint = "/partition-root";
+                swap.swapfile.size = "4G";
+
+                # Override existing partitions.
+                extraArgs = [ "-f" ];
+
+                # Subvolumes must set a mountpoint in order to be mounted,
+                # *unless their parent is mounted*.
+                subvolumes = {
+                  # Subvolume names do not necessarily correspond to
+                  # mountpoints, despite the structural resemblance to a file
+                  # path.
+                  "/rootfs" = {
+                    mountpoint = "/";
+                  };
+                  "/nix" = {
+                    mountpoint = "/nix";
+                  };
+                  "/persist" = {
+                    mountpoint = "/persist";
+                  };
+                  "/persist/home" = {
+                    mountpoint = "/persist/home";
+                  };
+                  "/swap" = {
+                    mountpoint = "/.swapvol";
+                    swap.swapfile.size = "4G";
+                  };
+                };
               };
             };
           };
         };
       };
     };
-    zpool = {
-      rpool = {
-        type = "zpool";
-        datasets =
-          let dataset = options:
-                let default = {
-                      type = "zfs_fs";
-                      mountOptions = [ "noauto" ];
-                      options = {
-                        "com.sun:auto-snapshot" = "false";
-                      };
-              };
-              in lib.recursiveUpdate default options;
-          in
-          {
-            "local" = dataset {};
-            "darlings" = dataset {};
-            "local/root" = dataset {
-              mountpoint = "/";
-              postCreateHook = ''
-                zfs list -t snapshot -H -o name \
-                  | grep -E '^rpool/local/root@blank$' \
-                  || zfs snapshot rpool/local/root@blank
-              '';
-            };
-            "local/nix" = dataset { mountpoint = "/nix"; };
-            "local/home" = dataset {
-              mountpoint = "/home";
-              postCreateHook = ''
-                zfs list -t snapshot -H -o name \
-                  | grep -E '^rpool/local/home@blank$' \
-                  || zfs snapshot rpool/local/home@blank
-              '';
-            };
-            "darlings/persist" = dataset { mountpoint = "/persist"; };
-            "darlings/home" = dataset {
-              mountpoint = "/persist/home";
-            };
-            "reserved" = dataset {
-              options = {
-                canmount = "off";
-                mountpoint = "none";
-                reservation = "5GiB";
-              };
-            };
-        };
-      };
-    };
   };
-
-  fileSystems."/persist".neededForBoot = true;
 }