What do you think of using Pathname for the DEVICE_PATH ```DEVICE_PATH  = Pathname.new('/dev')```  I don't like specifying slashes if we don't have to.  I think this line would be better as:

```ruby 
DEVICE_PATH.join(@volume_group.name, @name)
```

See http://www.ruby-doc.org/stdlib-1.9.3/libdoc/pathname/rdoc/Pathname.html#method-i-join