The difference comes from using different units, GiB vs. GB. See
https://en.wikipedia.org/wiki/Binary_prefix
$ units '232 GiB' GB
* 249.1081
Don't know about encryption, more worried about losing the password myself
than getting black bagged.
Regarding the terminal closing thing, switch to the terminal window and hit
Ctrl+Z, that will suspend the process in it. Then input bg which will make
the process run in background and now you should be able to close only the
terminal window. (easiest with Ctrl+D)
