nixos-config/common/hardware/btrfs.nix

{
  lib,
  pkgs,
  ...
}: {
  boot.initrd.availableKernelModules = [
    # Btrfs CRC hardware acceleration
    "crc32c-intel"
  ];
  
  services.btrfs.autoScrub = {
    enable = true;
    interval = "monthly";
    fileSystems = lib.mkDefault ["/"];
  };

  systemd.timers."btrfs-snapshot" = {
    wantedBy = ["timers.target"];
    timerConfig = {
      OnCalendar = "weekly";
      Persistent = true;
      Unit = "btrfs-snapshot.service";
    };
  };

  systemd.services."btrfs-snapshot" = {
    script = ''
      set -eu
      ${pkgs.btrfs-progs}/bin/btrfs subvolume snapshot /home /snapshots/home/$(date +"%Y-M%m-%d_%H-%M-%S") -r
    '';
    serviceConfig = {
      Type = "oneshot";
      User = "root";
    };
  };
}