From 343f4608f01b8699e7c073ec31992d186c03fd10 Mon Sep 17 00:00:00 2001
From: Romain Paquet <rpqt@rpqt.fr>
Date: Mon, 16 Mar 2026 19:50:48 +0100
Subject: [PATCH] Set disk schema of machine: renoir to
 btrfs-single-disk-subvolumes-impermanance-rollback

---
 machines/renoir/disko.nix | 171 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 171 insertions(+)
 create mode 100644 machines/renoir/disko.nix

diff --git a/machines/renoir/disko.nix b/machines/renoir/disko.nix
new file mode 100644
index 0000000..e01292c
--- /dev/null
+++ b/machines/renoir/disko.nix
@@ -0,0 +1,171 @@
+# ---
+# schema = "btrfs-single-disk-subvolumes-impermanance-rollback"
+# [placeholders]
+# mainDisk = "/dev/disk/by-id/nvme-CT1000P3PSSD8_2313E6C35BC1" 
+# ---
+# This file was automatically generated!
+# CHANGING this configuration requires wiping and reinstalling the machine
+{ config, ... }:
+let
+  # Adjust, to match the partition's priority.
+  rootPartition = "${config.disko.devices.disk."main".device}-part3";
+in
+{
+  boot.loader.grub = {
+    efiInstallAsRemovable = true;
+    efiSupport = true;
+  };
+
+  disko.devices = {
+    disk = {
+      "main" = {
+        name = "main-af36cf221b9a469888f67f3404be01a5";
+        device = "/dev/disk/by-id/nvme-CT1000P3PSSD8_2313E6C35BC1";
+        type = "disk";
+        content = {
+          type = "gpt";
+          partitions = {
+            "boot" = {
+              size = "1M";
+              type = "EF02"; # for grub MBR
+              priority = 1;
+            };
+            "ESP" = {
+              type = "EF00";
+              size = "500M";
+              priority = 2;
+              content = {
+                type = "filesystem";
+                format = "vfat";
+                mountpoint = "/boot";
+                mountOptions = [ "umask=0077" ];
+              };
+            };
+            "root" = {
+              size = "100%";
+              priority = 3;
+              content = {
+                type = "btrfs";
+                extraArgs = [
+                  "--force"
+                  "--label root"
+                ];
+                subvolumes = {
+                  "@root" = {
+                    mountpoint = "/";
+                    mountOptions = [ ];
+                  };
+                  "@nix" = {
+                    mountpoint = "/nix";
+                    mountOptions = [
+                      "compress=zstd"
+                      "noatime"
+                    ];
+                  };
+                  "@home" = {
+                    mountpoint = "/home";
+                    mountOptions = [ "compress=zstd" ];
+                  };
+                  "@persist" = {
+                    mountpoint = "/persist";
+                    mountOptions = [ "compress=zstd" ];
+                  };
+                };
+              };
+            };
+            #"swap" = {
+            #  size = "8G"; # adjust
+            #  content = {
+            #    type = "swap";
+            #    discardPolicy = "both";
+            #  };
+            #};
+          };
+        };
+      };
+    };
+  };
+
+  fileSystems."/persist".neededForBoot = true;
+
+  # https://www.notashelf.dev/posts/impermanence/#impermanence
+  boot.initrd.systemd = {
+    enable = true;
+    services.rollback = {
+      description = "Rollback BTRFS root drive to a pristine state";
+
+      wantedBy = [ "initrd.target" ];
+      after = [ "initrd-root-device.target" ];
+      before = [ "sysroot.mount" ];
+
+      unitConfig.DefaultDependencies = "no";
+      serviceConfig.Type = "oneshot";
+      script = ''
+        echo "Mounting root btrfs drive..."
+        mkdir --parents /mnt
+        mount --options "subvol=/" ${rootPartition} /mnt
+
+        if [[ -e /mnt/@root ]]; then
+            mkdir --parents /mnt/root.old.d
+            timestamp=$(date --date="@$(stat --format=%Y /mnt/@root)" "+%Y-%m-%dT%H:%M:%S")
+            echo "Moving @root to 'root.old.d/$timestamp'..."
+            mv /mnt/@root "/mnt/root.old.d/$timestamp"
+        fi
+
+        delete_subvolume_recursively() {
+            IFS=$'\n'
+            for subvolume in $(btrfs subvolume list -o "$1" | cut --fields 9- --delimiter ' '); do
+                delete_subvolume_recursively "/mnt/$subvolume"
+            done
+            echo "Deleting subvolume '$subvolume'..."
+            btrfs subvolume delete "$1"
+        }
+        echo "Deleting very old subvolumes..."
+        for subvolume in $(find /mnt/root.old.d/ -maxdepth 1 -mtime +30); do
+            delete_subvolume_recursively "$subvolume"
+        done
+
+        echo "Creating new empty subvolume @root..."
+        btrfs subvolume create /mnt/@root
+
+        echo "Finished successfully. Unmounting..."
+        umount /mnt
+      '';
+    };
+  };
+
+  # Automatic local snapshots
+  # https://digint.ch/btrbk/doc/readme.html
+  #$ systemctl start btrbk-<instance>
+  services.btrbk = {
+    instances."nix" = {
+      onCalendar = "*/2:00";
+      settings = {
+        subvolume = "/nix";
+        snapshot_create = "onchange";
+        snapshot_dir = "/nix";
+        snapshot_preserve = "16h 7d 2w";
+        snapshot_preserve_min = "3d";
+      };
+    };
+    instances."home" = {
+      onCalendar = "*/2:00";
+      settings = {
+        subvolume = "/home";
+        snapshot_create = "onchange";
+        snapshot_dir = "/home";
+        snapshot_preserve = "16h 7d 3w 2m";
+        snapshot_preserve_min = "3d";
+      };
+    };
+    instances."persist" = {
+      onCalendar = "*/2:00";
+      settings = {
+        subvolume = "/persist";
+        snapshot_dir = "/persist";
+        snapshot_preserve = "16h 7d 3w 2m";
+        snapshot_preserve_min = "3d";
+      };
+    };
+  };
+}