replace with real hardware configs

nix/hosts/hardware-configurations/db-data-disk.nix

@@ -0,0 +1,28 @@
+{ lib, ... }:
+
+# Second disk for db-host: the Postgres data directory lives on /dev/sdb, kept
+# separate from the OS disk (/dev/sda). The whole disk is one GPT partition,
+# ext4, mounted at /var/lib/postgresql — so the cluster data dir
+# (/var/lib/postgresql/17, the upstream NixOS default) sits on this drive and
+# survives an OS-disk rebuild.
+{
+  disko.devices.disk.disk2 = {
+    device = lib.mkDefault "/dev/sdb";
+    type = "disk";
+    content = {
+      type = "gpt";
+      partitions = {
+        data = {
+          name = "data";
+          size = "100%";
+          content = {
+            type = "filesystem";
+            format = "ext4";
+            mountpoint = "/var/lib/postgresql";
+            mountOptions = [ "defaults" ];
+          };
+        };
+      };
+    };
+  };
+}

nix/hosts/hardware-configurations/disk-config.nix

@@ -0,0 +1,55 @@
+{ lib, ... }:
+{
+  disko.devices = {
+    disk.disk1 = {
+      device = lib.mkDefault "/dev/sda";
+      type = "disk";
+      content = {
+        type = "gpt";
+        partitions = {
+          boot = {
+            name = "boot";
+            size = "1M";
+            type = "EF02";
+          };
+          esp = {
+            name = "ESP";
+            size = "500M";
+            type = "EF00";
+            content = {
+              type = "filesystem";
+              format = "vfat";
+              mountpoint = "/boot";
+            };
+          };
+          root = {
+            name = "root";
+            size = "100%";
+            content = {
+              type = "lvm_pv";
+              vg = "pool";
+            };
+          };
+        };
+      };
+    };
+    lvm_vg = {
+      pool = {
+        type = "lvm_vg";
+        lvs = {
+          root = {
+            size = "100%FREE";
+            content = {
+              type = "filesystem";
+              format = "ext4";
+              mountpoint = "/";
+              mountOptions = [
+                "defaults"
+              ];
+            };
+          };
+        };
+      };
+    };
+  };
+}

nix/hosts/hardware-configurations/hardware-configuration.nix

@@ -0,0 +1,14 @@
+{ config, lib, pkgs, modulesPath, ... }:
+
+{
+  imports =
+    [ (modulesPath + "/profiles/qemu-guest.nix")
+    ];
+
+  boot.initrd.availableKernelModules = [ "ahci" "xhci_pci" "virtio_pci" "virtio_scsi" "sd_mod" "sr_mod" ];
+  boot.initrd.kernelModules = [ "dm-snapshot" ];
+  boot.kernelModules = [ ];
+  boot.extraModulePackages = [ ];
+
+  nixpkgs.hostPlatform = lib.mkDefault "x86_64-linux";
+}