{pkgs, ...}: {
  # Root filesystem.
  fileSystems."/" = {
    device = "/dev/disk/by-uuid/cac60222-9b38-4938-8b17-5fddd67e8e26";
    fsType = "ext4";
  };

  # Docker data directory
  fileSystems."/home/fern/docker/data" = {
    device = "/dev/disk/by-uuid/95461a94-ad91-43b9-b502-2b5d4496b84e";
    fsType = "ext4";
  };

  # Swap.
  swapDevices = [
    {device = "/dev/disk/by-uuid/55dfb275-75de-4519-8f98-3491cefed32b";}
  ];

  # Media HDDs.
  fileSystems."/mnt/hdd0" = {
    device = "/dev/disk/by-uuid/fcee0188-8ca1-4fda-81b7-f5920c79ab48";
    fsType = "ext4";
  };

  fileSystems."/mnt/hdd1" = {
    device = "/dev/disk/by-uuid/5d9dd538-79e4-4168-be91-e0b040155cb3";
    fsType = "ext4";
  };

  fileSystems."/mnt/hdd2" = {
    device = "/dev/disk/by-uuid/5a43b7dc-3e28-459e-824a-ad45b5475361";
    fsType = "ext4";
  };

  # Install some packages.
  environment.systemPackages = with pkgs; [
    mergerfs
    ansible
    (python3.withPackages (ps: [ps.ansible ps.pip ps.requests]))
  ];

  # MergerFS.
  fileSystems."/media" = {
    fsType = "fuse.mergerfs";
    depends = ["/mnt/hdd0" "/mnt/hdd1" "/mnt/hdd2"];
    device = "/mnt/hdd*";
    options = ["cache.files=partial" "dropcacheonclose=true" "category.create=mfs" "func.getattr=newest"];
  };

  # Media group.
  users.groups.media = {
    gid = 1800;
  };

  users.users.fern.extraGroups = ["media"];
}