{ pkgs, lib, config, ... }:

{
  imports = [];

  boot.supportedFilesystems = [ "zfs" ];

  # The 32-bit host id of the machine, formatted as 8 hexadecimal characters.
  # You should try to make this id unique among your machines.
  # Manually generated with : head -c4 /dev/urandom | od -A none -t x4 | cut -d ' ' -f 2
  networking.hostId = "69c40b03";

  # none is the recommended elevator with ZFS (which has its own I/O scheduler)
  # and/or for SSD, whereas HDD could use mq-deadline.
  services.udev.extraRules = ''
    # set none scheduler for non-rotating disks
    ACTION=="add|change", KERNEL=="sd[a-z]", ATTR{queue/rotational}=="0", ATTR{queue/scheduler}="none"
  '';

  # Ensure extra safeguards are active that zfs uses to protect zfs pools.
  boot.zfs.forceImportAll  = false;
  boot.zfs.forceImportRoot = false;

  boot.zfs.enableUnstable = true;
  boot.zfs.requestEncryptionCredentials = true;

  # Enables periodic scrubbing of ZFS pools.
  services.zfs.autoScrub.enable = true;

  environment = {
    systemPackages = [
      pkgs.mbuffer
      pkgs.zfs
    ];
  };

  /*
  # Enable the (OpenSolaris-compatible) ZFS auto-snapshotting service.
  services.zfs.autoSnapshot = {
    enable   = true;
    frequent = ;
    hourly   = ;
    daily    = ;
    weekly   = ;
    monthly  = ;
  };
  */

  /*
  fileSystems."/boot" =
    { device = "bpool/boot";
      fsType = "zfs";
    };
  */
  fileSystems."/" =
    { device = "rpool/root";
      fsType = "zfs";
    };

  fileSystems."/home" =
    { device = "rpool/home";
      fsType = "zfs";
    };

  fileSystems."/nix" =
    { device = "rpool/nix";
      fsType = "zfs";
    };

  fileSystems."/var" =
    { device = "rpool/var";
      fsType = "zfs";
    };

  fileSystems."/var/cache" =
    { device = "rpool/var/cache";
      fsType = "zfs";
    };

  fileSystems."/var/log" =
    { device = "rpool/var/log";
      fsType = "zfs";
    };

  fileSystems."/var/tmp" =
    { device = "rpool/var/tmp";
      fsType = "zfs";
    };
}