use a zfs mirror for storage

base.nix

@@ -7,6 +7,7 @@ with lib;
   imports = [ ./hardware.nix ];
 
   networking.hostName = "nixbitcoin";
+  networking.hostId = "d1af0f9b";
   time.timeZone = "UTC";
 
   services.openssh = {

deployment/2-format-storage.sh

@@ -0,0 +1,70 @@
+#!/usr/bin/env bash
+set -euxo pipefail
+
+disk1=/dev/sda
+disk2=/dev/sdb
+bootSize=512MiB
+# `swapSize` should equal system RAM.
+# This setup will create one swap partition on each disk.
+swapSize=${swapSize:-32GiB}
+
+# Remount already formatted storage
+mountStorage() {
+    if ! zfs get type rpool &>/dev/null; then
+        zpool import -f -N rpool
+    fi
+    mount -t zfs -o x-mount.mkdir rpool/root /mnt
+    mount -t zfs -o x-mount.mkdir rpool/nix /mnt/nix
+    mount -o x-mount.mkdir ${disk1}2 /mnt/boot1
+    mount -o x-mount.mkdir ${disk2}2 /mnt/boot2
+}
+
+if [[ ${1:-} == remount ]]; then
+    mountStorage
+    exit
+fi
+
+formatDisk() {
+  disk=$1
+  sgdisk --zap-all \
+   -n 0:0:+1MiB      -t 0:ef02 -c 0:bios-boot \
+   -n 0:0:+$bootSize -t 0:8300 -c 0:boot \
+   -n 0:0:+$swapSize -t 0:8200 -c 0:swap \
+   -n 0:0:0          -t 0:bf01 -c 0:root $disk
+}
+formatDisk $disk1
+formatDisk $disk2
+mkfs.fat -n boot1 ${disk1}2
+mkfs.fat -n boot2 ${disk2}2
+mkswap -L swap1 ${disk1}3
+mkswap -L swap2 ${disk2}3
+
+# ashift=12
+# Set pool sector size to 2^12 to optimize performance for storage devices with 4K sectors.
+# Auto-detection of physical sector size (/sys/block/sdX/queue/physical_block_size) can be unreliable.
+#
+# acltype=posixacl
+# Required for / and the systemd journal
+#
+# xattr=sa
+# Improve performance of certain extended attributes
+#
+# normalization=formD
+# Enable UTF-8 normalization for file names
+#
+zpool create -f \
+  -o ashift=12 \
+  -O acltype=posixacl \
+  -O xattr=sa \
+  -O normalization=formD \
+  -O relatime=on \
+  -O compression=lz4 \
+  -O dnodesize=auto \
+  rpool mirror ${disk1}4 ${disk2}4
+
+zfs create -o mountpoint=legacy rpool/root
+zfs create -o mountpoint=legacy rpool/nix
+zfs create -o mountpoint=none -o refreservation=1G rpool/reserved
+zfs set com.sun:auto-snapshot=true rpool/root
+
+mountStorage

hardware.nix

@@ -1,8 +1,24 @@
-# Do not modify this file!  It was generated by ‘nixos-generate-config’
-# and may be overwritten by future invocations.  Please make changes
-# to /etc/nixos/configuration.nix instead.
+# Storage deployment is defined in ./deployment/2-format-storage.sh
+
 { config, lib, pkgs, modulesPath, ... }:
 
+let
+  # When a device marked with `nonessentialDevice` is unavailable,
+  # booting succeeds and systemd marks the system as degraded.
+  # This allows the system to boot when one device fails.
+  nonessentialDevice = [
+    "nofail"
+    "x-systemd.device-timeout=10s"
+  ];
+
+  bindMount = srcPath: {
+    device = srcPath;
+    options = [ "bind" ];
+    # Silence warning:
+    # systemd-fstab-generator: Checking was requested for "<srcPath>", but it is not a device.
+    noCheck = true;
+  };
+in
 {
   imports =
     [ (modulesPath + "/installer/scan/not-detected.nix")
@@ -13,21 +29,46 @@
   boot.kernelModules = [ "kvm-intel" ];
   boot.extraModulePackages = [ ];
 
-  boot.loader.grub.enable = true;
-  boot.loader.grub.version = 2;
-  boot.loader.grub.device = "/dev/sda";
+  boot.supportedFilesystems = [ "zfs" ];
+
+  # Not needed
+  systemd.services.zfs-mount.enable = false;
 
-  fileSystems."/" =
-    { device = "/dev/disk/by-uuid/d070abe5-6a51-4ea5-9365-57828fd0dd30";
-      fsType = "btrfs";
-    };
+  # TODO-EXTERNAL:
+  # The filesystem definitions below can be replaced with zfs `mountpoint` attributes when
+  # https://github.com/NixOS/nixpkgs/issues/62644 has been implemented
+  fileSystems."/" = {
+    device = "rpool/root";
+    fsType = "zfs";
+  };
 
-  fileSystems."/boot" =
-    { device = "/dev/disk/by-uuid/66958700-90e2-4428-aed5-1cc850f202aa";
-      fsType = "ext2";
-    };
+  fileSystems."/nix" = {
+    device = "rpool/nix";
+    fsType = "zfs";
+  };
 
-  swapDevices = [ ];
+  fileSystems."/boot1" = {
+    device = "/dev/disk/by-label/boot1";
+    fsType = "vfat";
+    options = nonessentialDevice;
+  };
 
-  powerManagement.cpuFreqGovernor = lib.mkDefault "powersave";
+  fileSystems."/boot2" = {
+    device = "/dev/disk/by-label/boot2";
+    fsType = "vfat";
+    options = nonessentialDevice;
+  };
+
+  swapDevices = [
+    { device = "/dev/disk/by-label/swap1"; options = nonessentialDevice; }
+    { device = "/dev/disk/by-label/swap2"; options = nonessentialDevice; }
+  ];
+
+  boot.loader.grub = {
+    enable = true;
+    mirroredBoots = [
+      { path = "/boot1"; devices = [ "/dev/sda" ]; }
+      { path = "/boot2"; devices = [ "/dev/sdb" ]; }
+    ];
+  };
 }

website/static/index.html

@@ -29,7 +29,7 @@
 
     <h1>nix-bitcoin demo node</h1>
 
-    This webpage is hosted on a nix-bitcoin node (<a href="https://github.com/fort-nix/nixbitcoin.org/">source code</a>) running bitcoind, clightning, clboss, electrs, btcpayserver, and joinmarket. The node is deployed using btrfs on Hetzner Online.
+    This webpage is hosted on a nix-bitcoin node (<a href="https://github.com/fort-nix/nixbitcoin.org/">source code</a>) running bitcoind, clightning, clboss, electrs, btcpayserver, and joinmarket. The node is deployed using ZFS on Hetzner Online.
 
     <h4>clightning</h4>
     <code>