def minimum_disk_space_used
      # TODO: replace Aruba.config.physical_block_size
      # with something like Aruba.config.fs_allocation_unit
      dev_bsize = Aruba.config.physical_block_size

      stat = File::Stat.new(to_s)

      blocks = stat.blocks
      return (blocks * dev_bsize) if blocks

      typical_fs_unit = 4096
      typical_dev_bsize = 512 # google dev_bsize for more info

      block_multiplier = typical_fs_unit / typical_dev_bsize
      fs_unit_size = dev_bsize * block_multiplier
      fs_units = (stat.size + fs_unit_size - 1) / fs_unit_size
      fs_units = 1 if fs_units.zero?
      fs_units * fs_unit_size
    end
def minimum_disk_space_used
      # TODO: replace Aruba.config.physical_block_size
      # with something like Aruba.config.fs_allocation_unit
      dev_bsize = Aruba.config.physical_block_size

      stat = File::Stat.new(to_s)

      blocks = stat.blocks
      return (blocks * dev_bsize) if blocks

      typical_fs_unit = 4096
      typical_dev_bsize = 512 # google dev_bsize for more info

      block_multiplier = typical_fs_unit / typical_dev_bsize
      fs_unit_size = dev_bsize * block_multiplier
      fs_units = (stat.size + fs_unit_size - 1) / fs_unit_size
      fs_units = 1 if fs_units.zero?
      fs_units * fs_unit_size
    end
TODO: Aruba.config.physical_block_size could be allowed to be nil
 (So the unit size can be autodetected)
 Report minimum disk space used

 This estimates the minimum bytes allocated by the path.

 E.g. a 1-byte text file on a typical EXT-3 filesystem takes up 4096 bytes
 (could be more if it was truncated or less for sparse files).

 Both `File::Stat` and the `stat()` system call will report 8 `blocks`
 (each "usually" represents 512 bytes). So 8 * 512 is exactly 4096 bytes.

 (The "magic" 512 bye implied makes the value of "blocks" so confusing).

 Currently Aruba allows you to set what's called the `physical_block_size`,
 which is a bit misleading - it's the "512" value. So if you somehow have a
 "filesystem unit size" of 8192 (instead of a typical 4KB), set the
 `physical_block_size` to 1024 (yes, divide by 8: 8192/8 = 1024).

 Ideally, Aruba should provide e.g. `Aruba.config.fs_allocation_unit`
 (with 4096 as the default), so you wouldn't have to "divide by 8".

 (typical_fs_unit / typical_dev_bsize = 4096 / 512 = 8)


 @return [Integer]
   Total bytes allocate

 TODO: this is recommended over the above "blocks"