hosts/ni: convert to btrfs-based filesystem setup

configs/nixos/ni/default.nix

@@ -6,6 +6,10 @@
 
     # Include the results of the hardware scan.
     ./hardware-configuration.nix
+
+    # Include the disko configuration.
+    ./disko.nix
+
     ./modules
   ];
 
@@ -27,10 +31,6 @@
   # Enable the display manager of choice.
   services.xserver.displayManager.gdm.enable = true;
 
-  disko.devices = import ./disko.nix {
-    disks = [ "/dev/nvme0n1" ];
-  };
-
   services.openssh.hostKeys = [{
     path = config.sops.secrets."ssh-key".path;
     type = "ed25519";

configs/nixos/ni/disko.nix

@@ -1,48 +1,64 @@
-{ disks ? [ "/dev/nvme0n1" ], ... }:
+{ config, lib, ... }:
 
 {
+  disko.devices = {
     disk.primary = {
-    device = builtins.elemAt disks 0;
+      device = [ "/dev/nvme0n1" ];
       type = "disk";
       content = {
-      format = "gpt";
+        type = "gpt";
-      type = "table";
+        partitions = {
-      partitions = [
+          # You can't really have a btrfs-layered boot so this'll have to do.
-        {
+          ESP = {
-          name = "root";
+            priority = 1;
-          start = "512MiB";
-          end = "-8GiB";
-          part-type = "primary";
-          content = {
-            type = "filesystem";
-            mountpoint = "/";
-            format = "ext4";
-          };
-        }
-
-        {
-          name = "ESP";
             start = "0";
-          end = "512MiB";
+            end = "128MiB";
-          bootable = true;
+            type = "EF00";
             content = {
               type = "filesystem";
               mountpoint = "/boot";
               format = "vfat";
             };
-        }
+          };
 
-        {
+          root = {
-          name = "swap";
+            size = "100%";
-          start = "-8GiB";
+            type = "8300";
-          end = "100%";
-          part-type = "primary";
             content = {
-            type = "swap";
+              type = "btrfs";
-            randomEncryption = true;
+              extraArgs = [ "-f" ];
+
+              subvolumes = lib.mkMerge [
+                {
+                  "/root" = {
+                    mountOptions = [ "compress=zstd" ];
+                    mountpoint = "/";
+                  };
+                  "/home" = {
+                    mountOptions = [ "compress=zstd" ];
+                    mountpoint = "/home";
+                  };
+                  "/nix" = {
+                    mountOptions = [ "compress=zstd" "noatime" "noattr" "noacl" ];
+                    mountpoint = "/nix";
+                  };
+                  "/swap" = {
+                    mountpoint = "/.swapvol";
+                    swap.swapfile.size = "8G";
                   };
                 }
+
+                (lib.mkIf config.services.guix.enable {
+                  "/gnu" = {
+                    mountOptions = [ "compress=zstd" "noatime" "noattr" "noacl" ];
+                    mountpoint = "/gnu";
+                  };
+                })
               ];
             };
           };
+        };
+      };
+    };
+  };
 }