btrfs-subvolumes.nix

{ disks ? [ "/dev/vdb" ], ... }: {
  disk = {
    vdb = {
      type = "disk";
      device = builtins.elemAt disks 0;
      content = {
        type = "table";
        format = "gpt";
        partitions = [
          {
            type = "partition";
            name = "ESP";
            start = "1MiB";
            end = "128MiB";
            fs-type = "fat32";
            bootable = true;
            content = {
              type = "filesystem";
              format = "vfat";
              mountpoint = "/boot";
            };
          }
          {
            name = "root";
            type = "partition";
            start = "128MiB";
            end = "100%";
            content = {
              type = "btrfs";
              extraArgs = "-f"; # Override existing partition
              subvolumes = {
                # Subvolume name is different from mountpoint
                "/rootfs" = {
                  mountpoint = "/";
                };
                # Mountpoints inferred from subvolume name
                "/home" = {
                  mountOptions = ["compress=zstd"];
                };
                "/nix" = {
                  mountOptions = ["compress=zstd" "noatime"];
                };
                "/test" = {};
              };
            };
          }
        ];
      };
    };
  };
}