nixos/hosts/common/disks/btrfs/standard.nix

{
  type = "btrfs";
  extraArgs = ["-f"];
    subvolumes = {
      "/root" = {
        mountpoint = "/";
        mountOptions = [ "compress=zstd" "noatime" ];
      };

      "/nix" = {
        mountOptions = [ "subvol=nix" "noatime" ];
        mountpoint = "/nix";
      };
  
      "/swap" = {
        mountOptions = [ "noatime" ];
        mountpoint = "/.swapvol";
        swap.swapfile.size = "8192M";
      };
    };
}